You're right, target sucks. Every bride I've talked to who registered at Target had problems... but I felt like we HAD to anyway... and we've also had problems with duplicates,etc. The main thing is they're really hit or miss about updating the registry... so people don't realize they're giving you something you already have.
For our wedding we have three registries and I've been really anal about making sure that if 2 of the stores offer the same product, we register for the cheaper one. Even the people who don't have a walmart near them (where is that?!

) could still shop your registry online.