@ Brighterbits

I'm pretty new, so take this with a grain of salt as it's just what I've gleaned recently and from reading the comments of others.

Coinbase is a gamble that breaks down (as I see it) roughly as follows:

50% chance - you will have no problems making transactions that take 3-5 days (this is the standard ACH time and is DEFINITELY the banks fault, and it's archaic and stupid)
30% chance - you will just have your transactions cancelled before they take any money from your account
*18% chance - they will take your money, hold it for 3-5 days, and then just cancel your transaction and (within a couple of days) return your money, without any profit or loss to you
2% chance - they will take your money, hold it, and then just cancel your transaction at which point your money goes into limbo and you never see it again

**This seems like the most common scheme/problem people have run into - They can theoretically make a boatload off your money by having & holding those coins and if there's an uptick in the market just act as if your transaction never went through.

I have NOT read of anyone having unauthorized withdrawals from their banking institution, so I don't consider that a threat.

Good luck!