I don't have the freeview model only the satellite one, however the main differences seem to be.
The satellite model can be used to access multiple satellites giving access to thousands of free radio and Tv channels. The freeview model is restricted to those from your terrestrial transmitter so future expansion is very limited. New narrow beam capacity at 28.2E will be increased in the next year or so with new satellites so there is a lot more potential for future services.
It's not possible to record HD channels without encryption on the Freeview box it is on the satellite one.
The Freeview box can operate as a media streamer with a limited number of formats and will later offer additional on line services with the TV Portal. The satellite box can only play back external video with the aid of a free piece of software. Both allow archiving to an external HDD.
The newer Freeview box has a more powerfull processor so is likely to be more responsive when the cpu is carrying out more tasks.
In my experience the satellite signal is more robust especially during tropo lift conditions. There have been occasions when my Freeview signal has been near unusable. Only lost sat services once during heavy snow (fixed with a broom
). For many sat may well be the only option to get a full channel line up. (Lot's of people will finish up with a Freeview-Lite service with only 2 SD and 1 HD mux)
The satellite box is now generally stable and awaiting a promised fix for the inability to record the time shift buffer and the cessation of recording after a power cut.
The freeview box still has teething problems with surround sound to an external AV system due to the different audio compression used on Freeview
There is currently 1 more HD channel on Freeview and the posibillity of a 5th in future (that's likely to be it for many years). On Freesat there is currently only 3 HD channels on the epg (The other ones can be viewed in fta mode giving ITV1-HD Granada (the only free to air full-Hd channel at 1920 x 1080), ITV1-HD-London, STV-HD and Luxury Life-HD). There are some SD channels on Freeview not on Freesat (and vice versa). All HD channels on Freeview are 1440 x 1080.
Personally I don't find the UI on the Foxsat-hdr a problem. The epg can be a bit slow to navigate when the cpu is say recording two HD channels at the same time and replaying a 3rd one.
If you can afford it having both is the best option.