With the limited info to go on, here's my view on this.
Personally, I'd always pick 'great team-average product'; reason being, the great team can fix an average product and perhaps create a dozen more. However, an average team with a great product could just be a stroke of luck, but doesn't promise consistency.
That said, we need to understand what 'great team' means. People that just gel well, or enjoy spending time with each other is not a great team. If that were true, we could've just called on our buddies to run the show whenever we took off. A great team needn't like spending time with each other initially.
However, a great team must be one where each member feels as strongly about the objective or purpose of the company/ product as you do, because that is why all of you have come together; to accomplish something.
If that's not working as planned, take them outside of your work environment, and discuss frankly about the objective, the current status, and why things are shaping up as planned? Hope this helps. Good luck!