OK. Let's get a few things straight here. Only if it's a GoDaddy name is it worth backordering at GoDaddy. The instances of them catching a non-GoDaddy registered domain is extremely slight because they cannot compete with the big backordering guns of SnapNames/NameJet/Pool. Only on the chance that one of these don't capture the domain do GoDaddy have any real chance, and even then they are competing with many other dropcatchers.
Then again. It is better to wait for the (GoDaddy registered) domain to appear in their GoDaddy Auctions (Formerly TDNAM) because if you place a backorder it will show up as the first bid on the domain. Whereas if you didn't backorder it, you could snap it up at the last moment anonymously, or even wait for it to drop into their $5 bargain bin.
For non-GoDaddy registered domains, it depends who the registrar is. Each backorder company has it's own tie-ups with affiliated registrars. Normally it is good enough to only bid at the dropcatcher affiliated with the domain's registrar. But to be safe, you can bid at SnapNames/NameJet/Pool. It won't cost you anything for the bids unless you win the domain, but you ensure you are at the table, in case, by surprise, one of the other two dropcatchers captures the domain. Which happens occassionally.
Having said all that. Where is the domain registered? What is the expiry date? How much do you want this domain?