I used to be a big fan of mesquite when I used a water smoker and an offset. I continued to use it on turkey breasts after I bought my electric smoker.
I read on this forum that mesquite is perfectly acceptable in high heat, charcoal fire type applications, but that in the lower heat of the electric smoker it tends to leave a bitter after taste.
I didn't really notice it myself until reading it here, but it was definitely there. Probably not as pronounced on pork ribs. I stuck with hickory after that.
Since then I have experimented with several varieties of wood. Electric smokers use very little wood, so treat yourself to a variety pack one time and experiment a bit. Here is an excellent source.
http://www.nwsmoke.com/