http://www.amazon.com/gp/aw/d/B003ZX86ZU/ref=mp_s_a_2?qid=1329915998&sr=8-2
This is what I use everyday in the truck. I also have a Garmin Rino very similar to the one you posted. I haven't touched the Rino since I bought the Nuvi. I bought an extra suction cup mount so I can quickly move it from vehicle to vehicle.
The only downside to the Nuvi is that it does not give as much info as the Rino. The Rino (and other handheld like the one you posted) will show names and locations of mines, springs, and various other interesting things near you. This is the case when using Topo 2008 software with both units.
Upsides for the Nuvi are numerous. It is far more user friendly, shows more roads than the Rino when using just the stock software, is faster to navigate with, and is a hell of a lot cheaper to purchase.
Whichever one you get, you will need to purchase additional software to show trails. The Nuvi does show some, but the Rino doesn't show anything offroad until you load maps on it.
Edit: the Rino is waterproof.