I found myself holding onto a lot of GUSD for accumulating interest on BlockFi. I believe GUSD has the same model as USDC, so I'm fairly comfortable with holding it.

Tether definitely makes me nervous... both in the way that it doesn't appear to be backed at all, and how nonchalant so many people seem to be about that. I try to avoid it whenever I can, but who knows how much it'll matter if I avoid it if the community as a whole loses faith in USDT. It seems to me (as someone very new to crypto) that it would be fairly disastrous for cryptocurrency as a whole if that were to happen.