I use different wallets for different purposes. I don't like multi-currency wallets because I don't like to keep all my eggs in one basket. I use Electrum for bitcoin and MetaMask for Ethereum and its tokens. I also sometimes use MEW. First of all, ease of use and security are important to me.
If you are talking about Myetherwallet app than I can't support you. I tried to move from the MEW website to apps but for that was very bad experience. I use Coinbase for BTC holding and Ethereum website. New currency are involving to the cryptocurrency everyday, how many wallet will you use?