I just thought I'd mention an experience I had with Compubank (when they used to give ClickMiles which I would then use to transfer to AA). First, you had to use the card at the merchant as if it was a credit transaction (generally meaning you sign your name, and no PIN required). I assume that this is because then the merchant pays a credit card merchant fee which ultimately is a source of funds for the mileage program at the card issuing bank. However, the charge then hit my Compubank checking account as a "debit". Generally, as soon as I made a purchase on the card, I would see a hold on my checking account for the amount of the "charge". The actual charge would of course come through shortly thereafter or days later and, in some cases, the hold on the account was removed at the same time as the real charge hit my account. Other times, however, I was not so lucky. Sometimes, the hold would stay on for a day or two after the charge had been posted to my account, thereby tying up otherwise available funds for those one or two days. Had this been my primary checking account, checks would have bouced, etc. during these days when my account had these "dangling holds". At the time, Compubank told me that this phenomenom was common with debit cards and that there was nothing that could be done -- the hold time was established at the time of the charge and did not necessarily fall off when the charge came through.

Hopefuly, this was just a Compubank issue and maybe not all banks have this problem. I just thought I'd warn those who get one of these cards for the first time. Leave some cushion in the account at least until you know the bank's policy on this --- and have seen it in action.