I just received an email from a friend of mine I was querying on the subject, who owns a fully-blown professional studio, also mixes live sound, and is still running an ADA8000. Here's what he had to say, regarding studio recording:
I changed my setup back to a more traditional way of recording: Micīs and lines into the mixer, from there to the interfaces. This way I donīt have a problem with latency, which was pretty annoying. I used to have to adjust buffering etc. to get rid of the latency. Now I donīt.
Using the mixer when recording also gives me better control over the gain, and certainly better control over EQ, as the interfaces have only a gain pot per channel, no EQ, not even a attenuation pad on the gain pot.
The UMC1820 does indeed have an attenuation pad on each channel, but I don't think that would have much to do with latency anyway.
So, as with most things in life, YMMV.
This article has some very interesting, related stuff that I learned a few additional things from:
http://www.basic-home-recording-studio.com/latency.html