Thanks for the input, I actually installed both. The idea was to run 15-20 mins of each and make a call.
However Witcher 2 runs like toffee on my machine whilst ME2 runs maxed out silky smooth, so ME2 gets the go.
Make sure you have ubersampling disabled. It kills framerate without noticeable benefit. With it disabled, game runs well and looks stunning
http://abload.de/img/witch1ocj2y.png
http://abload.de/img/witch2kqk0f.png
meh, never bought any of the DLC and it didn't really take anything away from it at all.
Most of the DLC doesn't really add much.
There is a FAQ for all the DLCs here - http://www.reddit.com/r/masseffect/comments/1ad5ev/mass_effect_dlc_faq/
I am sorry.. but this is complete nonsense. The DLCs add a lot. The prothean character in ME3 is one of the best of the trilogy. Shadowbroker, Leviathan, Citadel...fantastic, must have DLCs.
I agree that Bioware's DLC policy is terrible, especially when their DLCs are never on sale.
But I definitely recommend getting all the story ones.