I did a bunch of stroller comparisons before picking one to bring my sons in. They are 2½ and 4 and are both tall (my 2½ year old is 38½" and my 4 year old is 44"). We had a Graco front/back double that was great when they were smaller but it's a monster when it's folded and VERY heavy. It's too hard to steer now with all that weight so I sold it. We also have a sit and stand and took that on our first trip. It did OK but my 4 year old wasn't thrilled that if he wanted to sit, he had to sit facing backwards and it was a problem if the little one (21 months at the time) wanted to nap and I reclined him, then his older brother couldn't sit, he had to stand. It wasn't too bad on that trip b/c it was DH and I with my parents so between DH and my Dad, he was up on their shoulders a lot.

When DH and I went on our own with them this spring we took a Graco side by side that I got at a yard sale for less that $10 and it did great! They were both comfy in it, it wasn't too wide to fit through doors and down aisles. I had no trouble getting it through crowds although we go early and are headed out before it gets really crowded and are back after our few hour break. My oldest's head hit the top of the canopy but didn't prevent it from being extended over them. It did bother him though. Also, if my oldest wanted to recline (happened a few times, he even napped once), his head sort of hangs off the back so he was forced to hold it at an odd angle.
The Graco side by side fell apart after that trip so I was picking a new one before our upcoming trip. I am taking them alone and we are meeting 2 of my girlfriends and their kids there (one is sharing our room also with her kids and no DH and the other will be there with her kids and her DH). Since I'm going alone with them I want a double b/c I want to be able to strap them both in if need be!

I did an extensive search to find the right one. I ruled out the Graco side by side b/c of the canopy hitting DS 4s head (he's now 6 months older and taller too). We tried the Jeep umbrella one and even DS 2 was tall enough that if he let his feet slip off of the strap footrest, he was kicking the wheels. DS 4s feet could drag the ground. The canopy is also pretty small on that one. I narrowed it down to either an Inglesina Twin Swift(sells for $199) or a Chicco Citta Twin ($140) and decided on the Citta Twin just because my oldest won't be stroller size for much longer so why spend more than I have to. Both of these strollers are umbrella folding so they are compact when folded (the Graco side by side folds flat but still wide), both have TALL reclining seats (DS 4s head doesn't hang off) and independent hoods so one can be covered and the other open...no fighing over that.

They are also HOODS rather than canopys so they are domed giving more head room and better sun coverage. You can also sort of adjust the height of the hood. The leg rests extend to make the seat a little deeper which prevented DS 4s feet from dragging or kicking the wheels. It also makes a nice long reclined seat for my 2 year old if he wants to nap.

The Inglesina has GREAT resale value. The Chicco is a new model but a "used only a few times" one sold not long ago on eBay for $125 so I figured I'll take good care of it, use it for what we need it for then sell it.
The Chicco also comes with a custom fit rain cover for no additional cost. It has nice wide seats too. My 2½ year old can even sit with his knees up in a sort of "criss cross applesauce" position with one knee up and be very comfy. I can post a pic of them in it if you'd like. They both like it and are very comfortable in it. It's easy to push and steer with them in it and on the mall trips and at a birthday party at a local zoo, I've had no problems fitting through any doors or anything. I got it when BabyAge.com had a 10% off sale and $3.95 shipping so it was like $127. I'd like to have found something cheaper but I didn't want to have problems with DS 4 being mad about the canopy hitting his head and not wanting to leave it out to cover his sleeping brother or have DS 2 kicking the wheels all day.
Chicco Citta Twin
Inglesina Twin Swift