Gemini itself is well known, but without some more details on the collateral that they require and their risk management it is a hard no. I've been trying for the last 3 weeks to find more hard information, without much luck. Lots of marketing, not a lot of facts. It is like Celsius' and BlockFi's programs, except so far I have found that BlockFi has more collateral required.
If there was something like BlockFi or Gemini Earn, even if the rate was 2% vs 3% or whatever, that insured your investment with a reputable third party insurance, it would be something to consider.
The question is for their rates, is it worth risking your BTC when they are not insured, you don't know about their underwriting and you are not holding the keys?