The Goodmans GHD1621F2 is a Freeview twin tuner PVR which usually means you can record 2 Freeview channels whilst watching something already recorded. If you want to record something from your VM box you can only record the channel you are watching.
The V+ is a 3 tuner PVR that works with Cable. You can record 2 VM channels whilst watching a 3rd live VM channel, some say you can record 3 channels at once but the jury's still out on that one.
You cannot, however, record or watch any Freeview through the V+.
I have Sky+ but it's basically the same thing. My set-up is a digital TV (Freeview Tuner built in), Sky+ and a basic DVD Recorder that also has a Freeview Tuner (Philips DVDR-3480). This allows for recording 2 Channel's from Sky while watching a pre-recorded show while using the DVDR to record a Freeview channel to DVD or, if I so wish, to watch a
live TV channel, while all this is going on, with the TV's tuner to watch a Freeview channel.
Oh and I can also use the DVDR to archive the odd bit of stuff from the Sky+.