Let me start with the "I Love Guitar Center" part:
I visit my local Guitar Center often, and have never experienced anything but great service and a great atmosphere. I'm certainly not one of their "big" customers, but between me and Tamara we've bought several instruments there and often pick up strings and accessories. Mostly, I drop in at least a couple of times a month to look at their used guitar wall and check out the acoustic room. They know me, they're friendly, and they're usually local performing musicians who have the latest scoop on who's playing where, etc. They're effectively a local music store in all the right ways.
Online, my experiences until recently were similarly fine. I usually order online through Musician's Friend, which they own and which is as good as it gets, but have occasionally bought harmonicas and other small items directly through Guitar Center's site, either for shipment to my home or "ship to store" with pickup.
My current experience with them online sucks, though.
They had a $49.95 USB MIDI controller keyboard on sale. I had a $30 Guitar Center gift card, so I went to their site, used the gift card, and paid the balance by debit card. Easy, peasy.
A few minutes later, I got an "order canceled" email. No explanation as to why it was canceled, just a note that it might take 5-7 days for my refund to process.
I got on their support chat to ask what was up. Turns out that although the item was listed as "in stock and ready to ship," it was out of stock. OK, no problem -- maybe there was an order run and the site just couldn't deduct from inventory as fast as the orders came in. Did they know when the item would be back in stock? Nope.
On the refund end, the debit card was not problematic. It was just a "pending" transaction that disappeared quickly.
On the gift card end, I dropped in every couple of days for 10 days to check the balance. It was always zero. Finally, I went back to support chat to ask about that. Turns out they don't refund to a gift card, they just give you an account balance. Which shows up nowhere on the site, but which I'm assured will be a payment option in the shopping cart.
So, I go to look at the keyboard. It's listed as "in stock and ready to ship." Surely after ten days that means they got more of them in, right?
I add it to my cart. I go to payment. No option for paying with an "account balance" of $30 that I supposedly have.
This time, instead of support chat, I actually call. Friendly, helpful service. Yes, I see that you have a $30 account balance. Yes, I can take your order over the phone, apply the account balance and take your debit card for the rest. Huzzah!
Five minutes later, email: Order canceled. Apparently the phone order receiver couldn't tell, at point of order, that the thing was still (or again) out of stock.
Will I use Guitar Center's online ordering system again? Yes, one time -- to spend the $30 that's trapped in that system. After that, never again. If I'm buying from Guitar Center online, it will be through Musician's Friend.