I've been to Mammoth. It's aptly named. There is an incredible variety of terrain. They have an outstanding terrain park. They have a lot of high speed lifts. Under the something different category, Mammoth was the first time I saw a coyote from the lifts and they have double fist sized pine cones. The village gondola was under construction while I was there. This should have simplified the logistics of getting to/from the base area to/from civilization (i.e. center of town). There is also a decent bus system, but I enjoyed having a vehicle to get around. It's not easy to get to and it is expensive, but Mammoth is on the must do list for serious skiers.
I went to Mammoth this past June. It was my first real trip to a western resort so my review may be somewhat uneducated but here it is anyway. Like Rusty said, Mammoth is aptly named. There's a ton of terrain open for the lower-intermediate up to the very advanced and it's all served by high-speed lifts. It's not very well suited for beginners. The upper 2/3 of the mountain is primarily advanced only but the lower 1/3 offers more than enough to keep the intermediate entertained and challenged. Afterall, the lower 1/3 still means more than 1,000' of vert.
Now on to things I know more about: Mammoth brews some awesome beer. The Mammoth Pale Ale is excellent, if not true to its style. The fish tacos were the bomb. The overall atmosphere was very relaxed and friendly (I'm sure it's a little more hectic mid-winter).
Lastly, don't let accessibility of the location scare you. The drive from Reno to Mammoth is amazing. Your first view of Mono Lake is breathtaking. We were even escorted by bald eagle for a few miles of our trip. The roads were not overly curvy so I imagine winter travel isn't too bad but chains are probably required.
Thanks for the info guys. Now who wants to sign-up and come along on the trip?
I'm assuming there are a lot of people here who haven't skied Mammoth. It's worth the trip... I haven't heard 1 really bad thing about it. A few instructor friends of mine went last spring... came back absolutely raving.
What casino will you be at? I'll be at the Reno Hilton at about the same time. If you're looking for a place to eat while you're in Reno, I'd recommend Rapscallions. A little pricey but not ridiculous and definitely worth it.
Not 100% set in stone yet. Most likely the Peppermill. We'll only be there Fri. night flying out Sat. afternoon on the back end of the trip.