For portability, this one cannot be beat, and it's top notch for quality with a 10 year warranty!
Positive Product Points
Simple to use (a monkey could use it)
Produces a consistent grind and is fully adjustable
10 year warranty on the grinding mechanism
Negative Product Points
The handle won't store inside the bottom, that would make it much more portable.
I use this for my travel and office grinder. It produces a consistent grind and is adjustable for most any grind, though I only grind for drip. Extremely portable and the warranty is incredible! $90 from SweetMarias, a bit high, but considering the warranty on the grinding mechanism, you can't beat it.