"not true, it's the same as it is now."
Not quite true!
The new system (should) automatically refund the "unused tax" when the seller sends in their V5C to DVLC, previously you had to send in two sets of forms: V5C and V14.
The unsatisfactory part of the change is the whole transfer of ownership piece; the V5C still has to be posted to DVLC and their service guarantee is for a new V5C to be issued 2~4 weeks after they received the V5C from the seller. It seems that the only way for a new 'keeper' to tax a newly acquired vehicle is in person at a post office. However, this ignores why the car is kept, obviously when I drive the car away from the seller it is still legally taxed (until the end of the day on which the transaction occurred) however I cannot legally keep it parked on the road for several days until I get round to visiting a post office (which will be a city centre one which will require me getting the car out to drive to it...)
Tellingly, the DVLC website gives very few details around this side of the change and hence I suspect it wasn't totally thought through; if the DVLC website is to be believed, I don't need to produce a valid insurance certificate if applying at the post office...