The quality of Plesk 10 is far below that of Plesk 8. How on Earth did it pass QC? It's much harder to use, much uglier, and much buggier. The updater bugs out, the migration tool completely fails repeatedly and inconsistently, and the entire package is twice as complicated as it used to be.
We've had a Plesk 8 VPS for many years now. GoDaddy forces it's users to reprovision if they want the additional disk space, memory, and bandwidth they are paying for when the plans are upgraded. So basically we've been forced to upgrade to Plesk 10. Plesk 10 is so awful we're going to just leave GoDaddy and Plesk behind and do everything the good old fashioned way. It's all extremely disappointing really; Plesk 8 was so great.
Incase Parallels wasn't aware, GoDaddy has no interest in supporting Plesk or keeping it's customers satisfied. It's really a convenient business arrangement: Parallels sells a product which would never pass any reasonable quality control process and makes a mint from GoDaddy buying it. GoDaddy pawns off support costs from the super buggy software they CHARGE for to their customers and just points them to Parallels. Guess who loses? The users.