I've only commissioned one fancel so far so I
might not be of much help to you.  I know that
this topic has been posted a few times here so
searching might help too :)

I commissioned the fancel below from forkysanime :
http://www.geocities.com/forkysanime/

I think they did an excellent job on my cel and
they include the sketch too :)
They also were very friendly and have reasonable
prices.

Here are a few other fancel artists that have been
recommended by others.  They also usually have a
gallery of their work for you to look at :

http://www.niisan.com/eyegrey/
http://www.lvcm.com/lialane/ 
http://www.hyperenity.com/mainpage.htm

I personally don't see anything wrong with fancels
as long as they are stated as just that.  Most
people prefer original designs instead of screen
cap fancels but mine is from a screen cap.