Snap Names, Name Jet, and Pool have the most horsepower by far as they as each has a large group of registrars behind them. Go Daddy is much cheaper but they have fewer feeds and probably a not very sophisticated catch algorithm. You do have to buy ahead but you can change your backorder to something else though if it is unsuccessful. If you truly apply for the best names, you will usually (but not always) loose at Go Daddy. If you REALLY want the name, you should apply at all of them. I once applied everywhere but Go Daddy and they got the name and it was an excellent one! If you are in this business, you need to be realistic. The competition is fierce. I have lost local geos for my county of 17K people (GreeneVA.com & Ruckersville.com). Neither is a 'drop of the day' but that didn't stop my unincorporated, populated 'spot' going for $1,700 and the other going for use on a charter fishing boat named 'Green Eva'. Be prepared for disappointment. It usually happens or you need deep pockets. Sorry, but that's the way it is! Really good drops are few and there is no guarantee even for mediocre names. Nothing 'belongs' to you!
As to Go Daddy, caught drops do go to auction (as all do) if there are multiple requests. This started last year. It was a real bargain before that. Also, if the name is at Go Daddy or one of their registrars (Wild West, Go France, etc.) they will try to auction it at TDNAM.com first. If it is a good name, your Go Daddy drop position is useless as it will sell at TDNAM.com before it ever gets there. As others have noted, if the name is in the 'Pending Delete' phase, it matters not at all where it used to be. If it was at Go Daddy and wasn't sold at TDNAM, it likely has little to no traffic or revenue or it would have been purchased there. That doesn't mean that it is a bad name for potential development though but parking it isn't going to make you rich or likely even pay for the registration fee.
BTW - If you buy many Go Daddy drops, you should buy the 'Investors Edge' service. It costs $29.95 per month but you can buy or renew a domain with it and use a '$5 off $30' coupon from DealTaker.com to reduce the price. Drop spots then cost $11.99 each. You can then buy them in groups and use a '$15 off $75' coupon from our friends at Deal Taker too. Buy drops ahead of time and you can drop the service every other month or so.