For the infant phase I LOVED my double snap-n-go. Much less bulky than a graco tandem (which I pushed a friend's w/ just her toddler in it & could barely stear that thing!) & since my girls always fell asleep in their carseats it was great to be able to pop them into the snap-n-go and keep them asleep. We also did lots of stroller walks that first summer & since they were in their carseats, they fell right to sleep & I could see them & adjust the carseat sunshades to keep the sun off of them.
When they outgrew the infant carseats we got a Peg Perego Aria (side-by-side). We chose it based on it being lightweight, narrow enough to go through doors & folds up relatively small. We never used it much. Even though it's narrower than a wheelchair, I found it really hard to go shopping w/, it wouldn't fit back into the clothes racks & I wasn't about to leave the girls out in the aisle. I definately couldn't maneuver it back into the clothes racks if I was carrying/slinging one or both girls, which tended to be the norm. I was alot more likely to use a single stroller & sling one.
Last spring (about the time the girls turned 2) someone on the APMultiples yahoo group recommended this stroller https://shop.babyworld.co.uk/Display...aspx?which=642
and while it was pricey when you factor in shipping from the UK (since you have some time, you could watch ebay, I did see a couple but wasn't willing to wait), it was SO worth it. only one seat reclines, so wouldn't work in the newborn phase, but I think it would be a good stroller to follow the double snap-n-go. The legroom in the back seat is very narrow & the basket is small, but it's small enough to go anywhere a single stroller will go, so I don't stress about taking it even if the girls end up walking or being carried, because it's small & easy to maneuver. Since the basket is small I tend to just hang stuff off the handles, but that works fine.