Fun is subjective. I think this game is super-duper fun, considerably more fun than almost any other game I've played. But it's hard!!!!!!!
And the balance is... kinda dubious!!!!!! By which I mean, especially if you play as a gunner, you might die to things like suddenly being cornered by a Droideka/SBD/Wook/suicidal-red-style-saberist, popped by a sniper from some unexpected angle, or flanked/ambushed by a Jedi/Sith. You might die to a newbie teammate accidentally shooting/slashing you. You might die to a wild grenade bouncing over to you. In my opinion, the balance of the game seems to be most reliable if you play as part of an at-least-2-man closely-coordinated squad, with at least one saberist (Jedi/Sith) on the squad. A saberist and a gunner working together competently is more reliable and feels more balanced than a lone saberist (or even moreso a lone gunner). The game is not balanced for all "1v1" situations. Certain "power" classes like saberists, Wooks, SBDs, Dekas, and even uh CR3 clone troopers all definitely feel "overpowering" in 1v1s. But again, it works out pretty well once you start using teamwork to complement each other's strengths and weaknesses.
So balance-wise I could say "it's a team game," but with the caveat that honestly most players don't play it as such because they can get pretty good mileage off of either loner saberist or semi-loner sniper. Or because they're just newbies and have no idea what they're doing either way.
Stability isn't an issue in my experience.
The big key element is just that it's extremely exciting, and varied, and skillful.
Here's a recent vid from Gargos showing some exciting plays.
There's also this opinion vid which is full of the kinds of "hard info" (opinions plus basic facts) you're probably looking for.