I think the VLA does nice on bass, parallel guitar buss, and vox. I have even used it on the mix buss and had good results with heavier styles of music. It really has a good lowend for the most part. I do find that the highs go away with higher compression settings, but for a good deal of sources like bass and parallel guitar buss stuff this is ok. It isn't a very "fast" compressor and lacks attack and release settings. So for me, it rarely gets used on kick and snare or drum buss.
I think if you have a lot of highend compressors laying around, this compressor may not seem like a standout. However, if you are like me and have some micro-limiters, an Ashly SC-52, a Joemeek C2, and a MXR Dual Limiter, you'll certainly be able to find a use for a VLA.
To me among the lower model compressors, this thing is one of the best.