The 1.4 seems to use a 58mm filter size vs the 52mm on the 1.8. That I guess has me sold already, because I already have the kit lens, and a sigma 70-300 APO lens on the way. I am a sucker for bokeh too, and the fact that I can now use my UV and Polarizer filter on the 1.4 whenever I get it is just too pleasing.
BTW, has there been any problems with non sharp copies, or should I just go ahead and buy the first copy I find for sale for a good price?
unless it's a FD mount in which case i stand corrected 

