Aura: Humax's flagship entry to the Android TV market, and being based on Android (rather than their own proprietary build of Linux) "has legs" (as it were) with a route for adding facilities (such as new Internet TV services) without relying on Humax to provide it from scratch (Humax would likely still have to approve new apps before they could be installed, unless the Aura gets "jailbroken"). Very limited or impossible to "extract" recordings for unlimited use elsewhere (presuming you are interested in doing that), although recordings can be exported in LoDef for portable use.
HDR-FOX T2: ... The only Humax Freeview PVR for which there is a "hack", and therefore very popular with us, and IMO equalled only by the Aura.