I know that several of us have or have considered buying the Jag pull-on jeans so I thought I'd write a quick review once I'd worn mine a bit. I found them at TJ Maxx - they are bootcut and dark denim, with the usual front and back pockets. They do come up higher on the waist than my regular jeans, but it's comfortable because of the elastic waist. The model I bought was actually a plus-size 14, but similar to the one in the Finds below. I don't know if the plus sizes and regular sizes differ in fit. (A note on length: they are long enough for me with flats, but a little short for wearing with heeled boots or wedges.)
Overall I'd call my happiness level with them a B. I've got a big difference between waist and hip, and I find that I end up tugging the waist up on them fairly frequently. I might be able to tighten the elastic somehow but haven't tried it yet. When worn with shirt untucked, they look identical to regular jeans. The thing that makes them really handy is that they are wonderful for traveling. You can sit in them all day and not feel constricted or uncomfortable. I don't know that I'd wear them all the time, or buy more than one pair, but it's great to have them around for those days when you are stuck in the car or on planes all day. I think they would work great for anyone who's just had a baby, has abdominal issues or had surgery, or is an apple/rectangle shape.
(FYI, Jag also makes regular fly-front jeans as well, and I've seen some other brands start to do pull-on versions as well.)