Honestly if I were you I think you need to do a little more research. I would HIGHLY recommend not ordering till you have done a little more, just seems a lot of questions. They are valid questions but I suggest getting researching before you do any ordering.
I suggest looking up your exact electricity cost (include taxes/fees). After that look at ROI, research it at different percentages. Try different miners at ROI it is good practice if noting else. After all that... research miners a little more. Assuming you do all that then come back. Decide if your doing for profit or learning.... and see if that is possible.
Then start looking at buying. It easily could take day's to go through all of this, there is no need to rush decision.
Okay, I know already that I want to do this for profits, and to learn. Mainly for profit. I'm just researching other miners and my electric I'll get back to you!
My suggestion would be, don't go for new miners, buy second hand miners and run them, as you will get those miners cheaper and will ROI even much faster compared to buying new miners. Remember, what I have known till now is, any miner that you buy works best just for 1 full year, so research and then buy.
I agree with buying old miners. But not because they will ROI faster. Both new and old miners are difficult to ROI if your electricity price is higher than $0.15 kWh. The old miners are cheaper, you will lose less.