If you don't want to read, here's the punch line: Earns a 9/10
The UA 6176 is overall an excellent preamp. It is extremely versatile and I feel comfortable using it for just about anything and knowing I'll get a great result.
This review contains no comparisons to the vintage 610 or 1176. It is unbiased from the perspective of current use an comparisons to newer gear in my rack.
This preamp is probably my favorite in the rack. It definitely scores high marks overall.
The 6176 is extremely versatile and very easy to use. If you have a clue what you're going for, this preamp can get you there very quickly. Besides this being my go to vocal and guitar preamp, I also find it very useful for warming up harsh percussion instruments such as bells or tambourines. The compressor brings through just the right harmonics particularly with those harsher applications, an the EQ is very useful and effective though simple.
There are only 2 minor qualms I have with this equipment as reflected in my ratings.
The 6176 is pricy. For almost $1k less you can get the LA-610 which has the same preamp and preamp features with another good sounding easy to use compressor, though it isn't quite as tweakable an I don't like it QUITE as much. Nonetheless, that is a large price point for what I would consider a less than proportional sonic improvement.
The 6176 also features an EQ that I wish had a few more dimensions to play with. A 3rd band in the mid range or a Q (or both) would be very useful (purists may disagree).
All in all this is an excellent piece of equipment and the ease of use and versatility far outweigh the very few minor cons. I am glad this workhorse is in my studio and I have come to rely on it almost daily. Once again, good job Universal Audio!
In my humble opinion, this preamp/compressor combo earns a 9/10.