Verbatim Blu-Ray - is 2x or 4x "better"

Here in Europe, the price of Blu-Ray drives has come down to a point where I consider it to be acceptable i.e. no longer in silly territory. I.e. I bought an LG BD-RW drive for €150 as part of a final overhaul for my current computer.
I’ve decided, spare cash permitting, to use BD-Rs as an alternative to hard drive storage for certain things (i.e. things currently on my hard drive that I have already backed up to DVD).

And so now, I bought one BD-R from GenesyDTP, list here:
http://www.genesysdtp.com/bluray.htm

They offer Verbatim BD-Rs in 2x and 4x varieties, and I ordered one 2x disc, figured there was no point in paying the extra buck for the extra burning speed as I won’t care what burning speed was used when the burn is done. All the same I wonder if there’s a quality difference between the two?

I am pretty sure the 2x will overspeed up to 6x so save that extra $1 a piece the 4x cost.

With the current firmware 2x seems to be prefererd for the LG.
It is a not so good 4x media burner and a terible 8x media burner !
See C’t (german computer magazine) test (summary can be found at cdrlabs) and some data found on the japanese sites.

So my vote is to use it with 2x media. It’s cheaper and better supported.