As I mentioned before, the PTS conditions were hardly ideal to test how well the choppa was balanced versus the all other Warhammer careers in group play. I fought a few 1v1s, which I will comment on below, but most skirmishes consisted of 75% choppas and slayers. I can only really speculate on how well they will fit into the game. Don't be surprised if we see some major balance passes on the choppa once it goes live and people start reaching rank 40.
The biggest balance complaint I heard during testing was that Git To Da Choppa was overpowered, mostly because slayers do not have access to a similar ability. I found many choppas spamming GTDC extremely overpowered, but that won't happen very often on the live servers. How do I know this? Blackguards were introduced as a new class several months ago and they are rare at rank 40. Simply put, new classes that are patched into MMOs tend to not be as popular as the original classes (exception: deathknights from WOTLK). I just don't think we'll see swarms of choppas dominating the live servers like they did the test server.
Generally, I don't get the feeling that choppas are imbalanced, but we'll have to wait and see to be sure. Here are a few examples of classes that decisively beat me in 1v1 on the test server: two-handed ironbreaker, grenade-chucking engineer, warrior-priest, and sword and board swordmaster. I predict that I wouldn't fare well against a well-played bright wizard, shadow warrior, or knight of the blazing sun either. That doesn't sound imbalanced, does it?
Overall, I had a lot of fun testing out the choppa. My main character is a rank 40, renown rank 40 squig herder, so I'm used to seeing the game through the eyes of a DPSer. I was constantly pulled between wanting to play conservatively and throwing caution to the wind on a suicide run. Thankfully, you can play the choppa either way, so it doesn't force you into one particular play style. Yes, your role is to charge into the fray and get your hands dirty, but how far you take it is up to you. Sometimes whipping yourself into a frenzy is advantageous but sometimes it's a quick trip back to the war camp.
I got the overall impression that this career was balanced but only time will tell if that is truly the case. They certainly perform well in both PvE and RvR but should always be wary of pulling boss aggro or drawing focus fire in RvR.
I especially liked the versatility between the mastery paths. AoE Wrecka spec can be extremely fun if you have a healer but I found it to be too suicidal for my liking given that there weren't enough healers on the test server to make it viable. Two-handed Hitta spec was fun but a bit challenging to micro-manage all your exhaustive blows. Given more time to play around, I would probably warm to it. Savage spec was my favorite as it gave me the most survivability and was easy to master. The lack of weapon restriction was also nice. This allowed me to do great single-target damage with two choppas instead of one.
The biggest thumbs up I can give the choppa is that it was fun to play. Green. Orc. Primitive hunk(s) of metal. Choppa chop! How can you go wrong with that?