TERRAIN, snowfall, vertical, glades, lifts, bumps, has character, lodging options, customer service
pricey, becoming more "resorty", not the best place for beginners, low intermediates, and park
Let me start off by saying that this place is great, but not everyone will love it as much. If you are looking for a large variety of wide open cruisers, large snowmaking coverage, perfectly manicured trails, good terrain parks, and lots of beginner options, you are probably better off at places like Mount Snow, Okemo, Stratton, Killington, Sunday River, or Stowe. That's not to say Sugarbush doesn't have those amenities: they just don't have as many wide open cruisers, groom as much, have as much snowmaking coverage, and have as many beginner areas and terrain parks as those other places. If, however, you love glades, steeps, BIG vertical (for the east), variety, powder, and natural terrain and bumps, you will love this place. Think of it as a bigger Mad River Glen with more amenities and lodging, faster lifts, and slightly more options for beginners and intermediates, but not any less challenging.
Beginners: Beginners don't have as much variety as some other places. For first timers, on Lincoln Peak, there is the Welcome Mat (magic carpet) and village double. There is also one green off of the Gate House express quad, but that's pretty much it. Over on Mount Ellen, there is another beginner area, and some more greens higher up, but going up the mountain may be intimidating for newbies, so they can get bored pretty fast The thing about Sugarbush is once you have mastered their greens, it is a pretty big step up to their blues. Many of their blues would be blacks at a lot of other places in the East, which is why this place isn't as good for beginners.
Intermediate: Decent intermediates have a lot of options, though again, the blues here are a step up from blues at other places. Some of the best on Gadd Peak (Superbravo Lift) are Snowball to Spring Fling (one of the few boulevards here), Murphy's Glade (really a trail with some trees dotting the middle), Birdland (under the lift), and lower organgrinder (black on the map, but one of the few blacks at Sugarbush that can be managed by intermediates). Off of the summit of Lincoln Peak (Heaven's Gate Triple), there is Jester, a delightfully twisty groomer. Upper organgrinder is a lot tougher than lower, so I wouldn't recommend it to intermediates. Ripcord (under the Heaven's Gate lift) is a double black, but is occasionally groomed. When it is, it can be managed my a strong intermediate, and is uncharacteristically easy for a double black at Sugarbush. However, it is usually bumped up, and a lot tougher when it is. There is nothing on castlerock for intermediates, and the blacks and double blacks there are the real deal, so don't try to go there even if you are a budding advanced skier; there is a large warning sign at the bottom of the lift, so those who don't belong there don't have to worry about inadvertently ending up over there. Off of the Gate House quad, there are some nice blues, including Sleeper, a nicely treed groomer. Off of the North Lynx triple, there is Birch run, a nice sunny area, great for intermediate bumps. On Mount Ellen, there are a couple of the boulevards that are sparse at Sugarbush, such as Cruiser, Rim Run, Which Way, Inverness, and Elbow. Try taking Rim Run from the top down the full 2,600 vert to the bottom-lots of fun. One of the things I love about the blues at Sugarbush is that each has character, such as being narrow and having some trees dot it.
Advanced: This is where Sugarbush really shines. I'm not going to be as comprehensive as I was with Intermediates; I'm only going to talk about on-map stuff, I am not giving up my stashes :)
Off of Superbravo, there is Stein's Run, which is wide, has some great bumps, and a perfect steep fall-line pitch. They make a lot of snow on this trail, so this is one of the last trails to close at the end of the season. Up on Lincoln Peak, there is upper organgrinder, the old gondola line. It's steep, used to be groomed but not so much nowadays. Ripcord, the wide trail under the heaven's gate lift; it can sport some great bumps, but they groom it more than they used to: when groomed, it is easy. Paradise is a great somewhat treed run, but I wouldn't recommend doing it if it hasn't snowed for a while. Now we come to castlerock, the the section of the mountain I could swear was stolen from MRG. It is served by a slow, low capacity double, and a big, frankly worded sign at the bottom keeps the gapers away. Middle Earth and Castlerock run are fun and tough, but nothing compared to Liftline and Rumble. Liftline is steep with lots of cliffs to launch off of, but you can at least see its condition from the lift. Rumble, however, is one of the nastiest trails in the East. It has liftline's pitch, but is extremely twisty, much narrower, and has a lot of rocks, roots, and cliffs to negotiate. I would strongly recommend not doing this trail unless it is the deepest day of the year, you hate your skis, or you really REALLY know what you're doing. North Lynx has some nice bump runs, but nothing scary. Off of the summit of Mount Ellen, you have Black Diamond and FIS: steep, bumpy, and often icy. Mount Ellen has some of the best bumps in the east: I'm not going to mention every bump run on mount ellen because there are so many, but I will say the blacks on Ellen are tougher than on LP because they tend to groom more on LP.
Trees: Sugarbush is one of the best in the east for this, with 270 in of snow each year avg (not inflated like Stowe), and a large selection of glades, on trail and off trail. The only thing is that Sugarbush does not rate their glades, so for easier trees, try Eden on LP. Other than that, I wouldn't recommend trying your first tree run at Sugarbush; go to Killington, Sunday River, or Jay for that.
Park: Once again, this is not a good place for that, unless you consider natural terrain your park. There is one park on mount ellen, served by a double, but pales in comparison to Killington or Mount Snow.
Families: This is not the best place for families with mixed abilities because they will not even be able to ride the lift with each other. At Stowe, for example, the quad serves every ability, so friends and family of different ability will be able to meet at the bottom and ride the lift together. At Sugarbush, different lifts serve different abilities for the most part, so families will not be able to be with each other while skiing or riding. Families with park enthusiasts, again, will not be happy here.
Other things about the resort:
There are lots of lodging options, ranging from the ritzy (and expensive) Clay Brook hotel, to affordable condos, to bargain inns. I have heard that their ski school is great. Lift tickets are expensive, and on the rise due to base area expansions. The cheaper mount ellen only ticket is not really worth it, unless you are a local, because a lot of the best terrain is on LP. IMPORTANT: When they put up a thin cover sign, there is always a reason here. Sugarbush tends to be conservative about closing trails, as they don't make as much snow or groom as much as some other places. Trails here marked with a simple lollipop "Thin Cover" sign would almost certainly be closed anywhere else, and you really don't want to be ducking any closed ropes here. There is 2000 acres of backcountry in the slide brook basin, but I wouldn't recommend going there unless you're with someone who has been there before, or with one of the guided tours. Watch out for moose in there! The people here for the most part are very friendly, from friendly chairlift conversations (not found at Killington) to the extremely helpful customer service. You won't find the arrogant vibe of MRG skiers here. The lift system is great, with 5 high speed quads and slower lifts servicing the summits. I like that, because you are not committed to skiing top to bottom, if there is better snow up high or down low, and if wind closes the upper lifts (which it often does here) you can still ski the lower mountain, unlike some other places (*cough* stowe). Also, it keeps the crowding at the top down.
I hope this has been helpful (if you are still awake by now)!