I personally own fancels from four different 
artists, one of whom doesn't do commissions. And 
I love all of their work for different reasons. 
As stated before, everyone has an individual 
style. Who you should choose to go with should be 
dependent on what type of art you want rendered.

That said, I think that on a strictly technical 
level, Requiem is the best. She is capable of 
rendering even the most complex things into cel. 
Case in point, this cel. I think I will be 
floating for weeks. Subaru and Seishirou, from an 
X color manga picture

~kea