I'm the last person to ask about this - I'm afraid I'm a bit of a luddite in this area. I've never even recorded over a digital backing track at home.
My studio experience has been either working as a player/composer in a full-on pro studio, or recording a few guitar and/or vocal tracks at home with a very simplistic setup, always one-shot, no overdubs, no punch-ins (until last weekend, when I finally overdubbed parts on a couple of songs for hire). Back in the mid-80s I engineered some reasonably good (for the time) demo recordings with the old Fostex Model 80, but those techniques don't translate very well to modern technology.
I would seem that the latency would be highly variable due to the way 'net traffic is routed. There are ways within a given subnet to prioritize traffic, but I doubt that the average home subscription service will allow those flags to be passed through so that we can hog the neighbors' bandwidth.