The charter DVR situation is a mess. They have this 7 yr old Passport based software that feels more like it was written 17 yrs ago. It is an embarrassment to them. They keep hinting that something new might come out eventually, including cloud-based DVR solutions. But this keeps getting pushed back and they recently asked the FCC for a 2yr extension on some exemption regarding upgrading their service. So who knows. They had a deal going with TIVO which has a real nice interface, but they terminated that agreement for some unknown reason,.a year or so ago. If you have any choice, I don't recommend Charter at all, not at least until they provide a modern level of service.
And on top of all that, they have a pretty lousy HD channel offering, at least compared to DirecTV, Dish, FIOS etc. Yeah, they have the basic channels in HD, but many of they secondary ones are not provided in HD.