Coinbase have many issues. One of there main disadvantages is that they sometimes cancel orders (based on suspicion) just when BTC price increase significantly,And though you can't be totally sure but it's suspicious they do that to some customers that look trustworthy.
They claim that no human does that, but that is triggered by some kind of algorithm. I'd like to see that algorithm!
I would try Bitstamp first as their verification process is quicker than the other two. You will need a high quality scan of your drivers license and a high quality scan of a bill of some sorts with your address. Once you're verified you can print out instructions from their website to wire funds to their bank in Slovenia. Funds were confirmed the next day for me when I wired funds there. Fairly simple process. Took about a week.