This has hot, top, and new, with default being hot, but you can change the default comment sort on your user settings page.

Here’s the thing I wrote on it. I put a lot of thought into the hot ranking, although I’m sure it will need tweaking once we get some really active threads.

Reddit’s post and comment sorting are actually kinda fucked, they’ve done analysis and found the first comment is the top comment in like 90% of threads.