I don't think 'best' is the right description. They are obviously very different price points, and I don't feel that the Puma500 is 'better' than, for example, the Markbass LMIII. It is a touch different, and if you are willing to pay double for the much smaller size and a bit more 'clean clarity' it is probably worth the money.
The GK stuff is amazing for what it does... bright, aggessive, grindy tone, the Markbass stuff is wonderful for its warm, relatively neutral tone. The Genz Shuttle Max 9.2 is the king of EQ power and tight, controlled slam.
I own a Glock Blue Soul, which is significantly more expensive than the Puma900, and it sounds different also (unique combination of super powerful, warm, round low end with massive slam, and a crystal clear, hi fi top end).
Lots of stuff out there. I do think the TH500 is one of the best values out there, but as you found out, only if you enjoy the Aguilar tone profile that is a bit less clean than some amps, and a bit less bright than others... more 'fat, warm and punchy'.
As we discussed above, given you've found a pedal that you like for the dirt, IF you want to have your 'base bass tone' (I should trademark that!) to be clean and relatively neutral, it is hard to beat the Puma stuff, and the Markbass Big Bang comes close if you are on a bit more of a budget!
Okay well I've changed my opinion slightly from before. The truth is, I love the warmth and punch of some amps, its just that warmth (as i've seen with ampeg) often comes with some muddiness. I can't stand muddiness. So If there were an amp that had a nice warm punch in the lows and mids and a clear top end, that would be fantastic (oh hey, I just realized that's almost exactly how you describe the Blue Soul...).
That is my main problem with the TH500. When I hit any note past the high G, the lack of clarity in the high end is extremely obvious.
Considering the TH500 is the only amp I have interest in that I've been able to thoroughly test, I'm basically basing my entire description of what I'm looking for off of my likes and dislikes of that amp.

