At the moment Arbitrum is definitely the hottest ethereum layer 2 solution out there. They are still having a lot of attention at the moment because of that huge airdrop that they did that brought tens of thousands users tokens worth 1000$ or more. Then a few days ago i have read a statement somewhere that the TVL on the Arbitrum chain was higher than the TVL of Ethereum itself. This is absolutely makes sense to me, because now that the market is making stronger movements again the fees on the native ethereum chain are already up at 60 gwei again, which is just way to high. A uniswap trade costs 25$ at the moment.