I switched to "new comments" and don't want to go back to anything else. It has only advantages in my mind:

• It gives me a mix of older and very new threads (because new posting also counts as a comment).
• It makes sure different threads are shown to me after a short period of time already, making sure I do not get bored by seeing only things I've already seen.
• It reminds me of web forums with thread bumping, which I continue to think were one of the best ways to organize online discussions we've ever had.
• It still shows me more upvoted stuff more of the time because many other users sort by sorting methods that take upvotes into account, so such threads also get more comments usually.

One disadvantage is that occasionally I get several-month-old (or even year-old) threads at the top of my feed if someone has the brilliant idea to post in them. Doesn't happen very much though.