Bittrex is not a scam. It is a very serious US-based exchange with good security features, which you have to enable yourself. However, like all exchanges struggling to cope with the crypto boom these past weeks due to an insane amount of new registrations, it can take up to several weeks to get fully registered with an enhanced account, due to strict regulations and KYC procedures. Especially if you are not US based, since they compare your submitted data to local public records. It has the largest choice of altcoins, and you can trade ADA with BTC or ETH, not fiat. Only downside of Bittrex is the user-interface in my opinion, but they are working on redesigning it.
Here is the link to Bittrex Fees.
Binance HQ is Hong-Kong based, and falls under Chinese regulations which tends to be unstable these days on cryptos. Its servers are in Japan and South Korea. Much better interface in my opinion. Fees are interesting here is the link. 
SUMMARY
FREE DEPOSITS on both exchanges (apart from the inevitable network fees)
TRADE
Bittrex : 0.25% commission per trade
Binance: 0.1% commission per trade
WITHDRAWAL:
Bittrex: Free, but there is a network transfer fee built into the coin
Binance: Depends on coins + network transfer fee as well
VERIFICATION:
Bittrex: Enhanced account can take several weeks ( you cannot withdraw with a Basic Account)
BInance: No registration needed up to 2 BTC threshold deposit/withdrawal
Piece of friendly advice:
- When you withdraw your coins from an exchange or your wallet, ALWAYS do a test with 1 coin as a precaution to check that you haven’t been hacked and/or build confidence the first time.
- Always triple check that you have pasted the same address as the one you’ve copied. Another address and you might very well lose your coins
- Use a desktop link to Bittrex/Binance rather than Google Results that can be manipulated (such as this guy who got hacked for over 100k in BTC)
Finally, NEVER store your private keys on your computer. This guy got all is coins stolen this way.