What wallet you trust to put all of your bitcoins
no, i never store my btc in just one wallet because it is too risky.
(or if you use another currency too)?
I keep altcoin in exchange like bittrex, I recommend bittrex.
Does it have high fees?
the desktop wallet fee will be less than the wallet exchange fee, many have complained about it.
Do you care about fees or almost never move that coins?
I actively buy and sell coins so fee is I think very much.