Pros: uncrowded, kids ski free
Cons: upload/download to get to the main area
June Mountain can often seem like it's not worth it, since it's hard to justify going there instead of Mammoth, which is just down the road. It's true that June is smaller and gets less snow, but it also gets fewer people. I was at June during Christmas Break when the parking lot was completely full, and still found that I had most of the runs to myself. The only runs that are busy are the beginner runs. For a couple years now Mammoth Mountain Resorts have let kids 12 and under ski free, and this was of great value to me, with 3 small children. It was great fun taking my kids skiing and the affordability helped a lot.
A couple other things. June has one high-speed 4-person lift that goes up to a mountain with groomed intermediate terrain and another high-speed 4-person lift that goes up to a mountain with a mix of blue, black, and double black terrain. Also, while June doesn't get as much snow as Mammoth, it had good snow the week I was there. Good coverage, and even 5 inches fresh one morning. Because there's hardly anyone skiing the harder terrain there were great powder turns to be had all morning.
But Note: June is a great mountain for families once you get to the main area. It SUCKS getting up to the main area on the long, slow 2 seater lift that goes from the parking lot to the chalet. It's a bad bottleneck, especially late in the afternoon. I rode down in the cold and dark with my 6yo because we had to wait for a long time in line just to get down. It's a big hassle not just for the sake of time, but for crankiness of kids and having to hold your skis on the way down since there's no place to glide off at the end.