I'll second that, though I don't have any direct experience with the UAD's (I've oogled them frequently and used equivalents- I *love* emulations of classic hardware). I'm a Pro Tools and hardware guy so I haven't looked into VST and DirectX offerings for a while.
At least I wouldn't recommend the Waves too much. Waves stuff is good and I used to love them... but they sound really bland to me these days. On the other hand, within the overall context of bland, the Ren Comp actually offeres a fairly wide variety of sounds. Ren Verb is a very useable reverb. Waves is lots of control, a good range of useability and absolutely no soul. (shrug)
Their customer support and policies are somewhat questionable, as well. They just made iLok (USB hardware keys) they only way to use their software and tend to make upgrades expensive. Can't blame them- its tough making a living as a (pirateable) software company.
I've also used the demos of the Blue Tubes (by Nomad Factory) Bundle. Cheaper than most of your other options and very good for the price. A little more CPU hungry, but I hear they've addressed that issue with V.2 and above. They also don't require a &^$! iLok.
Take care,
Chris