Which perks and features should one look for in a wallet?
Thanks in advance
It depends on what would you like to do..
Personally I prefer to use Electrum (Bitcoin) and MEW (Ethereum) and particular lightwallet for strong / rare transactions, while using for 2 cents and fast access other wallets like Jaxx

I would recommend you wallets in which you can choose tx fee by yourself. I remember that one time I installed a mobile wallet taking 0.01 ETH as a gas fee (and that day the minimum gwei for transacting was 3 gwei)