I feel my 6176 has made a big difference. The best way I can describe it is that it places what I record in a solid and defined space (more so than what I can make happen with plugs without a lot of work).
Lack of thickness is no longer a problem. And with the right settings, it really is a break to not have to worry about things peaking when tracking. Some people don't like it - many suggest changing the tubes/valves. I'm happy with mine as is. I find that I use less and less compression, though, and just run stuff through it to get that "placing"-effect, warmth and slight limiting of the recorded signal.