If recording is important to you, I would also look into the differences between the boxes, the 360 is missing a lot of recording related features compared to the V6, many of which are unlikely to come to the 360 either due to being TiVo patents or just disinterest from VM (people have been asking for un-delete since the box was released for instance).
Some of the missing features are as follows; Quickplay (play 10% faster with audio), Wishlists (where you can set the box to record programs on certain subjects or featuring certain people), undelete, series link+, suggestions, setting of series links for programs not in the current TV guide, ethernet control, keyboard support via USB, turning off the mini-preview screen while browsing menus, switching between tuners with constant buffering, skip-back on fast-forward, 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 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. If the boxes are used by independent family members i.e. older children living at home, then there is also the issue of recordings being pooled across all boxes, so everyone's recordings are mixed up, rather than being separated. This also means that if there is a show that both people watch and one person watches and deletes it then it is gone for the other person as well, and can't be recovered due to the lack of undelete.
