The 360 is missing a number of features found on the V6, a number of these are TiVo patents so will probably never appear, one or two of them might, but people have been asking for undelete for years and there's still no sign of it. In return you get a few new apps, Disney+, AppleTV and Sky Sports+ (obviously you need to be subscribed to get those), plus voice control (if you like that sort of thing), though that wont work if you use a universal remote. The interface is more geared towards streaming rather than recording, so more clicks to navigate to recorded shows etc.
Some of the missing features are as follows; Wishlists (where you can set the box to record programs on certain subjects or featuring certain people), undelete, series link+, series link manager, suggestions, setting of series links for programs not in the current TV guide, ethernet control, keyboard support via USB, switching between tuners with constant buffering, skip-back on fast-forward, quickplay, default recording options, cancelling individual recordings from a series link, multi-channel series links, radio channels allowing recording of radio, separation of recordings between boxes, watching recordings when internet is not available, separate HD\SD channels, and probably a few others I've forgotten.
Also, extra boxes do not have their own hard disks or tuners (unless converted from a V6 box), so you lose storage space and recording ability and are also reliant on the main box being on to watch and set recordings and also on having a decent wi-fi signal (or ethernet cable) between the two boxes when watching recordings.