Honestly, whether they released it in September and called it the "finished product", or kept in beta for another month, just to release "the finished" product in early October with the offline/LAN support, I see no real difference between the two. The LAN support would have taken just as much time either way, so really the only difference was psychological or arbitrary in the end. They should have released "the finished product" with all the features they promised, but once again, it still would have taken the same amount of time, and there was no real benefits to the players for them to wait that extra month (that I can think of).
Overall, I've been very impressed with them, and will most likely drop $20 into their next game. I would give more but I just don't have that much money right now, and I've realized that I just don't care about the early alpha and beta privileges. I usually wait for the full release anyway before I really invest my time and energy into it. Sometimes betas can be really disappointing.
In the end though, I think of PA's "final product" to be a bit of a misnomer anyway. Uber is obviously a company that continues to support and update their games over time, as they have with Monday Night Combat, in the same way that Arcen does with AI War and many of their games. "Final product", in my opinion, is when the company has died or when the developers no longer exist anymore and even then, the ease of the game's moddability would give TA fans new material to enjoy for decades to come.