What size are you talking about? i presume it's the 42" model?
The V10 is a cracking tv and has held it's value quite well, where as the new G20 seems to give it a good run for it's money. As for the V20, all i know is that it will definately perform better than the V10 as i have already seen the G20 next to the V10 and both seem to perform pretty closely to each other, so that give's me an idea that the V20 will be better than the V10.
All it boils down to is how much have you seen a V10 going for? if it's a very good price and saving you allot of money compared to the new V20, then i would still consider the V10 or if the price is close to the G20 then i would head you towards that instead.
M