Hi,
 
This topic has surely come up many times over on CW forums though can't find a recent thread.   If someone knows a good thread,  please provide link.
 
What's a great vintage compressor plugin for Sonar?  There are so many on the market such as emulating classic LA-2A:   CW,  NI,  IK,  UAD,  etc.  The list goes on and on.   Are these mostly similar in behavior/performance or does one stand out?
Primarily need for vocals,  bass & drums.
 
Had my eye on NI Vintage Compressors or PSP Vintage Warmer2 but wanted to hear from fellow Cakewalkers. 
 
 

You should investigate Pro Channel all the modules. 

I highly recommend the ProChannel compressors.  The La2a especially.  And the 1176 is nice, too.  As are the 4K channel and bus compressors.
 
I haven't had chance to play with the Nomad Factory ones yet (included in X3).

+1 on the LA-2A Pro Channel module.

The Nomad Factory Fairchild type compressor sounds pretty cool too.

Leadfoot
The Nomad Factory Fairchild type compressor sounds pretty cool too.

I must check that out when time permits.  A Fairchild style compressor was the only one I felt I was missing.
 
I had got to the point of not wanting any more compressors - was really happy with all the ProChannel ones, and getting used to how they worked, but am looking forward to trying the Nomad Fairchild one.  I'm also enjoying the Nomad Pulteq EQ.
 
The Fairchild Compressor and Pulteq EQ were on my constant wish-list for PC modules..

Yeah I like the Nomad Pultec also. And I'm non stop using that LA-2A Pro Channel module! They did a great job on that one!

Vocals, Bass, Acoustic guitar - LA2A
Drums 1176 or DBX160 or nothing depending on how it was tracked and the type of music. 
 
The Sonar LA2A is a very good emulation compared to UAD as I have done that shootout. It actually misses some transients like the real hardware where as the UAD grabs them all. The 1176 in Sonar is not nearly as good as the UAD versions because although it grabs fast like a real 1176 but it doesn't have the same EQ curve or even similar. This is part of the signature mid range bump of a real 1176.
 
In my experience here are some of the better plug in compressors and I threw a couple of limiters in there as well:
For color
UAD 1176
UAD LA2A
UAD SSL G or E series
Sonar LA2A
Waves CLA compressors - any of them
UAD 160x
UAD SSL buss compressor
 
For clarity:
Softube CL1B
UAD Precision Buss comp
UAD Precision Limiter
Massey Limiter
Elephant

They're a little pricey but the Waves JJP Analog Legends are great!  The Puigchild is really nice (you get a mono and a stereo plug).  Just like a Fairchild, they have a very straightforward control set and they do deliver the classic colored sound just like the real deal!  The PC Compressors are great too....just like everyone else has commented.

I like the Waves API 2500 also.