Sierra at Tahoe is an excellent resort. I am a season pass holder and usually try to go on weekdays. Sierra is always crowded but the lift lines seem to move fast. On crowded days, even if you are on expert runs, there are always people cutting in front of you. The staff is extemely polite and tries to help you whenever possible. There is also really good food in the downstairs lodge.
If you are planning on coming up to Sierra, wait about three days after a storm because the snow is still good and the roads don't have chain control (The crowds are also much smaller). Sierra at Tahoe is a pretty good resort but is always extemely crowded. Next season I am getting a season pass to a place that is not as crowded. If you like big crowds, long lift lines, people cutting in front of you, and ice in some spots, then come to Sierra at Tahoe!