I have a NEC 1300 too, it burns in 4x max but it is enough fast for me, about 20-25 min. for a DVD +RW (2.4x). The 8x disk are not available yet in France so the 8x is not usable for the moment and it is only for the +R format.
I heard/read that the double-layer (8-9 Go) will arrive soon (i read from april to december
) but it seems that some burners will only have to "refresh" their software to burn a double-layer.
Not sure about it. I didn't read review on the LG but you should find some on specialized sites.