What cloud mining site do you use and why?

While I do not endorse cloud mining or leasing hashing power, I disagree that it is not profitable. Both parties are taking a risk: the party leasing the power is giving up their potential earnings by taking a bet that the price of BTC will never be worth the cost. The one renting out their hashing power is basically accepting "less risk" by making sure their power costs are covered. As for people talking about "ROI" ... that is the entire problem! You're all doing this not to support network, but for your own greedy selves. However, of course you're getting a "ROI": you are receiving a limited supply of bitcoin, which will be supplied less and less in the future. Your return comes out to be actual bitcoin units ... which are insanely valuable and useful. Especially for the future human world.

For cloud mining and leasing, I strongly believe it is a good thing: it gets people to see some form of what mining is like. Total newbies can experience from this and possibly profit. If they do not profit, it is a very small fee to pay for the education involved

For a profitable venture in "mining for USA dollar", of course leasing isn't the way to go. You need to do this all yourself, learn it all yourself, etc. Depending on the size of your operations, as well as the funds you are putting into supporting the bitcoin network, you have some options that can help you:

Co-locate with a mining service that charges you per kW -- this is generally much less expensive than a traditional data center, and because the centers themselves take care of hosting your machines, they should be prepared for the serious heat issues caused by mining equipment. Co-located with the right company can be a great idea, as you will likely save a lot of money and time since you don't need your own staff, network redundancy, or a plan for how you will handle the heat! You still manage the hardware yourself (which is easy if you understand how to work with mining pools, have your own wallet, etc.), but you at least own your hardware assets! An example of this type of service: https://bitcointalk.org/index.php?topic=725967.0

Another service is where you basically hand over money for purchasing machines and sign a contract. Using more formal words: you allow another (trusted) company to manage and host your mining operations entirely. The company could even manage your wallet if you wish (not a good idea unless you're a serious newb), which allows you to have instant liquidation of you want cash from your coins. Best of all, you retain ownership of the coins *AND* the hardware. This is really the best option if you want to maximize your time and your money to support the bitcoin network. My company is the only company I know of that offers something like this soooo...maybe this post will inspire other companies to do something differently and stop trying to make so much money off innocent people curious about mining