Well I made not 1 but 4 really extensive guides on how I feel the presets work for each race individualy and linked them all in one post here: http://larian.com/forums/ubbthreads.php?ubb=showflat&Number=605277#Post605277

The highlights of my research are as follows:

*Inquisitor is basicaly the fighter preset
*Shadowblade has the least amount of viable pathways (by this I mean that you can build on top of the free skills you get and not be forced to recreate your companion from mostly 0 upwards)
*Most presets favour 2 races and provide downsides to the other 2 (it's harder to level up certain races using certain presets, like lizzard + inquisitor) but there are some presets which favour 3 races and provides downsides to just one (conjurer can be very good for dwarves,elfs and humans but I can't imagine making a good lizzard conjurer for the early game outside of character creation)
*Fighter is the only preset where I can claim without a shadow of a doubt that Contamination is given here just to act as a dump skill,something you remove asap from your memorised spell list.