Cheap, Closest to Phila Metro Area, A+ Instructors, Short Lines
The Good: This is the place to go to learn to ski or to have your kids learn to ski. The instructors at the Ski School are good natured and expert at teaching first time to intermediate skiers. Given the close proximity to Philadelphia, you can get to Spring Mountain in about 30 minutes (from Chester & Montgomery Counties) and 40 minutes (from Phila, Bucks & Delco). The low price for lift tickets makes for a cost effective outing (weekend adult is only $35, a 10 lift ticket for any person any time is only $269 and good deals on lessons and rentals). Short lift lines (even on weekends) is another big plus. Oddly, this also seems to be a great hangout to read, as there were many folks in the lodge with books (probably parents of kids taking lessons). Finally, the outdoor food / hot chocolate concession is both convenient and cheap.
The Bad: While fine for honing your skills, the slopes offer little challenge for advanced intermediate and above skiers, and the Diamond Trails never seem to be open. Also, with the exception of the french fries (which are excellent) the rest of the cafeteria food is below average.
Overall: A good experience. I plan on returning with the family several more times this year.