Ok, I've been using this unit for a few weeks now.
A great combo (for me) is Google Nav (on my android phone in the car) to get into the area, and then using my GC to get to the cache. Most of my caches have been 1.5 miles or less from where I park. I'm a newbie, and using geocaching to lose wait, so I'll work up to the longer hikes later.
From my experience caching with my family (wife, 12 yr old son, 14 yr old daughter) it seems to be that you either get used to it right away (me & son), or it takes a bit of teaching (wife & daughter).
The dashboard on this unit kicks butt, and is damned accurate, but as someone else said it can be slow to update sometimes.
Not being able to update a cache's coordinates (you have to set a new waypoint with new coords instead) is a pain when doing puzzle or multicaches, but it can be done (did 2 today in fact).
Battery life is fantastic, in fact I use rechargeable batteries and have used it for a whole day without having to charge the batteries or swap them (I have 4 rechargeable AA batteries just in case).
Ok, this kind of rambled on, but I will say this: I love my GC, and it's a great upgrade for anyone using a mobile phone app for geocaching (as I was).
I may post again later if I think of anything else.