I currently hold most of my bicoins on blockchain.info, however my trezor should arrive in a couple of days, so I'll be using their wallet after that. I use mycelium on my phone as well.
I also use blockchain.info because when I forgot my coinbase wallet password, my friend told me to use blockchain. and it is good enough during this time. there are many features of it and the performance is good because it has blue colour. actually I forget how coinbase looks like and I have never used the other wallets so I cannot compare it with others well.
I also use the blockchain wallet because its an easy wallet can be good secured and is trusted, used by many people so it was a simple choice.