GoDaddy expiring domain names are just that -- expiring. They haven't expired yet. So, they won't appear in your account until they actually expire. To get a realistic expectation of when the name will enter your account, look in your account under Auctions -> Won. It will list the names you've won. Check the date carefully, and mark your calendar. Most of the time it works effortlessly, but I did once have a problem. You only have a few days to report a problem, and then you receive an email that your order has been completed. If there is a problem, you need to sort it out BEFORE you get that completion email, otherwise the name can be released and they no longer control it. Overall, I have been very happy with their service.

They have tonnes of cheap drops indeed.

I just purchased an expired name at Godaddy and after several days still not in my account. Tech support claims it takes an incredibly long 2 to 3 weeks before it gets in my account but why that long?

Domain registrar choice is definitely personal preference, although, personally, I'm not very fond of the GoDaddy system.  I agree with Mark though about the backordering and their system is effective when you're buying from auction or other sellers. However, I move any domains I win elsewhere first chance I get.

You should use GoDaddy when the domain that is expiring was registered through them. Check the WHOIS data to confirm. They would then be the best choice to place a backorder as they have priority to secure the name over other registrars during the pending-delete phase.

If you're interested in buying expiring domains - that is, GD is one of the largest marketplaces for such thing. This is a sole reason for going there .I don't use GoDaddy for registering new domains though. NameCheap.com is much more pleasant registration service.Try them. They're cheaper than GD and don't try to sell you their crap all around.