I am thinking about transfering 15 ether to bittrex to buy 300 Qtum. I dont know much about Qtum. Is it like NEO? I want to transfer most of my Eth and buy other coins that have potential to grow faster than Eth. What do you think about my decision to buy Qtum???
I would recommend you to do more research before you decide to buy! As far as I know QTUM is a modified version of the Bitcoin blockchain (combined with features of the litecoin blockchain or something like that). To be honest Im skeptical about QTUM because their CEO was accused of being a scammer somehow. But I also hold some since it was trading on $8, just to be on the safe side.
As you want to invest quite a lot of money in it, I would do more research first (my purchase was only 10 Qtum, so it wont hurt when things go south).
As for the wallet, the QTUM mainnet is up and running as far as I know, you should transfer the coins from Bittrex to the official wallet. Storing in MEW is not possible anymore as far as I know. But Im not sure, Im also still keeping the QTUM that I got on the exchange.