We have it, but rarely ever used it. To be fair, though, it was because my DS was much older and I just felt like I needed to have a double for long trips (zoo, Disney, etc.)
That being said we have never had any issue with it. When DD was in her infant carseat it cut into his space quite a bit, but him sitting/standing was still doable. The basket underneath is tiny and a real pain to get to, but not a deal breaker for me. It folds up flat enough, but is still really long if you have the carseat adapter on the front, so just keep that in mind. We have a crossover SUV and it was a tight fit. Overall, I still am really happy with it and would buy it again... if my little ones were closer in age!