It has been my experience that system can matter quite a bit with respect to player enjoyment and much of it comes down to how cumbersome the system is for what we are trying to do with it. If it's too cumbersome, it affects the fun.
For example, the players in my group have all played D&D in some form for most of our lives (our average age is in the low 40s). When we tried 4e out, we had a couple of enthusiasts, a couple of skeptics, and a pack of neutrals. After about a year or so, even the enthusiasts had come to find the futzing with powers more cumbersome than we were interested in enduring and we opted to return to 3.5, an edition in which players had a little more power to choose the degree of cumbersomeness they wanted and with which we were more proficient.
As another example, when one of our GMs started up an adapted Mass Effect campaign, he first chose GURPS as his system. But to model the technology and tech modularity, we were struggling with rolling a lot of dice, calculating a lot of damage against shields, and it was just getting to be a hassle. So we switched to Star Wars Saga Edition and it has been smooth sailing ever since because the mechanics were a lot less cumbersome fit (a limited selection of Force powers makes for some good biotics).
When I was in high school, we had both Champions and Villains and Vigilantes. We played the latter a whole lot more because, as superhero games go, V&V was a lot less cumbersome than Champions and a whole lot easier to teach to new players, particular with respect to character generation.