We have gone through 2 double strollers since my second was born 4 years ago(we get far more use out of them than the average person and the first one broke LOL). Both of them have been Sit-n-Stand models. My oldest is taller than average so when we went shopping for the double we had him sit in every single one we saw at numerous stores and he wasn't fitting in any of the styles that had a second proper seat. Then we found the sit-n-stand. At the time it was pretty much the only one on the market. Now there are quite a few on the market by several companies. Our new one we bought at Target. It's by Babytrend and is called the Sit N Stand LX model #7311. Think we bought it last year. My boys are 4 and almost 7 in a couple months. It's still really easy to stear, although if my oldest sits in the front it's finally getting impossible to control it LOL We go to Disneyland a couple times a month, it's been to several renaissance faires, the San Diego Comic Book Convention a number of times, a Star Wars convention in LA last year, Zoo a few times, Sea World, Legoland and on and on. We love it!! It's got good storage underneath as well and it doesn't get back heavy and tip over unless you've really hung too much off the back handles (we found out what too much was and trust me, most people won't try to put that much...we were at the convention) We looked at a couple other modle sit-n-stands when we were looking for our second and we really didn't like a lot of them, much smaller, but this one we love. We have yet to find anywhere we can't get around with it.
edit: also forgot to add, both my husband and I are pretty tall (5'9") and it's comfortable enough for us to push it, the handle bar isn't so low that we have to stoop like our old one as well as our single we had before.
This got to be a long post, sorry.