Personal opinion:

Never had a problem with Click and Buy (JUST DON'T HAVE MONEY LAYING IN THE C&B ACCOUNT AND THEY WON'T CHARGE YOU) Square will automatically pull from your bank account through click and buy when it comes time for payment. But if you put money in the account yourself and let it sit there....they are going to charge you to keep it there, that is why people don't like click and buy; its because they don't understand how it works for the most part.

Albeit I do agree they do seem like a shady version of PayPal because they don't clearly explain the above and want you to screw up and get charged out of the arse by them. Also it's not that some banks refuse business with them its just that they lack some of the mainstream precautionary methods (they have their own) and some banks don't accept that; also I believe but I'm not 100% certain that they don't accept any and all types of money so your bank might not be acceptable with them from that.

Personally I have a Wachovia/Wells Fargo account and its worked/s just fine on XI, not a problem and no hidden fees to date because I use the system correctly.