I've used Hashflare since several months ago, they're not scam at all. You can customize the pools and their ratio too as you wish, once a day. I have 1.7 MH on Ethereum, and it's profitable. I suggest you to invest in Ethereum as it's more faster than Bitcoin, cheap for miner's fee, and faster to mine than Bitcoin. Faster to mine means you need less money to mine.
Thank you for the advice, I think I will buy 1MH worth of Ethereum. Can I ask, how do you set the pools setting? I'm using their default setting.
I'm using default setting too, I'm too lazy to analyze each mining pool now. Allocating 100% to a strongest mining pool doesn't mean you get the most profit, you need to allocate to another mining pool too. Two heads better than one head, the mining power should be split so can be more profitable than just focused to one pool.