We have a Besafe Izi Combi bought in 2009. DS is heading for 18kg, he is big and tall and will be 3 later this month.
We would like him to stay RF as long as possible. I note that there are RF seats, as far as I can see potentially that would allow him to RF up to weight 25kg.
DH has just said "Is it worth it if he will grow out of a new seat very soon"? However, looking up weight charts, it looks as though 25kg is a weight attained between the ages of 5.5 and 9.5 years. So, quite a big spread, but he would have prob 2-3 years use, which doesn't sound so bad.
The ones which go from age 4 - 12 look as if they have much less restraint which I would be a bit concerned about, even if they are a lot cheaper (and no doubt beter than nothing).
The other thing is, how long would he be comfy in RF? He has been car sick 4 or 5 times (usually over me 
) and we had wondered whether RF contributed to this.
By the way we have a V70 (2006) but not with isofix. We could prob go for Volvo own brand but would have to do some more research.