i use the Logitech DFP and it is the best wheel i have ever used. and i used a few... its my 5th wheel in a decade or so, i have had (from memory) some wheel i cant even remember the name of... the madcatz thing the ferrari 360 modena (non FFB) the logitech MOMO Racing (black) and now the DFP...
I found the main advantage with the DFP is the fact i can choose the amount of rotaiton i want in the wheel, say NR2003 in game has 350 degrees of rotation in the steering, so i set my wheel to 350 and i have 1:1 stearing ration from ingame to my wheel.
few downsids are the buttons, there set out in PS2 format which is el crappo, but you can get MODS for the wheel from www.frex.com/gp which sadly are expensive but once bought would make this the best wheel ever IMO.
The pedals are the usual logitech rubbish though, i havent had problems (yet - touch wood) but i am expecting them