freitasm: I'd dare say the "average punter" is just moving from POTS to VoIP and won't have multiple lines, etc. Geeks rule, and therefore can do and ask for things "average punters" can't and won't.
I tend to agree. VFX appears to be aimed squarely at the average punter / home user who wants to move to VoIP, without any setup or ongoing config headaches. IMHO they (Xnet) have done a superb job of this - it just works as you'd expect, with one or two VoIP lines.
They haven't left geeks out in the cold though - by offering the OpenVFX service you can set up VoIP however you wish - the gotcha is that you take responsibility for any setup/config errors that may cause your bill to increase (fair enough, I believe)!
If you have a requirement outside the standard VFX config, no problem, just go for OpenVFX - it's a bit more work to set up, but that's all part of the fun of customising everything to suit your exact requirements :-)