Thanks. Do you have any experience with any of them?
I've used all 3 of them for several months. I'd rank them generally Nexo > Celsius > BlockFi. Those rankings could change depending on your situation or use case.
I have used Celsius as well as Blockfi. Another one to consider is ledn.io as it has/had better rates than the other two with higher deposit limits.
I never used them for a loan but only as a "savings" account to accrue more BTC.
I used all 3 simultaneously for around 6 months and they all performed as stated.
However, I was constantly paranoid that they were going to do a rug pull and in the end I felt that the 4 to 6 % return per annum was just not worth the risk of losing the capital.
They may well be legitimate businesses but history has shown us that there is a reason why we say "Not your keys, Not your coins".
I think I will stick with my lousy 200% by HODLing.