There's no reason you can't do both. But assuming you want to choose one... Consider that any given game is only a new pre-release title for one, usually short part of its project life cycle. Opportunities to gain experience at this part of a game project is comparatively rare. On the flip side, as long as your team sticks together you can get experience making new projects together literally whenever you want. I would not be in a rush to turn away from a rare opportunity to go chasing a common one. Of course, I'm biased. I tell people to make small projects in part so that they can reach this phase of the project as quickly and as often as possible. Anyone with some technical skills can make a game, but there are relatively few people who can also sell them effectively.