As far as I am aware, your only other choice for an HD DVR with TWC is a Tivo HD.
There is the older Series 3 or the new Premier which is advertised as having a much faster processor and some other bells and whistles.
The only problem with a Tivo is that you have to have a Tuning Adapter installed to be able to view the SDV channels, which is most of them.
The Tuning Adapter can be a real pain to get set up. It took me several truck rolls to get mine working because none of the techs knew how to do it.
Hopefully, the techs are now better trained.
If you want to learn about Tivo and Tuning Adapter issues, check out these threads...http://www.tivocommunity.com/tivo-vb...sprune=30&f=51
The Tivo surpases the TWC box in every way. But be prepaired for some headaches getting it working properly.