I have two boys, 4 and 2 (they will be almost 5 and 3 when we travel this fall). They both weigh between 30 and 35 pounds. We bought the Jeep Double Stroller. It is around $80 and often goes on sale at TRU. I took DH to the store with me to find one, as he will be the one unfolding/folding it while I get the kids on the resort buses. He pushes it a lot as well. We did find a Combi one at TRU that seemed way nicer, but we were not willing to shell out the extra $120 when the boys don't use it much, except for our trip, the zoo, mall, etc.
That being said, I have used it twice now at the zoo, many times at the mall, and a few times for neighborhood walks, and it is great. The boys can easily hop in and out on their own for zoo displays, (but we can easily strap them in when we need to) and the best part: it is so light to lift up into my car. The sun shield is iffy...I may buy a larger sun shield for our trip in Sept., and there is no understorage.