I like what I've seen from BlockFi so far after having some $BTC in there for the last couple months. I know they had a solid referral bonus program going where you could rack up some quick money but unfortunately my ref links are avoided like the corona. But based on when I put my $BTC in the account, I qualified for a special 2x bonus if I kept it in there for what I believe was just 30 or 60 days to qualify. I was a week late checking in on it but it was a pleasant surprise nonetheless, who doesn't like free cheese for holding $BTC in an account.