The someta has gotten a good review. I like the compact size and affordable price. I've been using a Red Hen model for a few years, but the someta looks intriquing.
I have had a Delorme Pn-20 which I like a lot. It is an older unit and is at times slow to redraw maps. It worked really well out in the Bisti Wilderness. I plan to replace it with a PN-40.
It took me a while to get used to the unit--and the DeLorme software but I like them a lot now.
Another vote for the Delorme units. I have used the PN-20 for 2 years and, once I got used to setting it up, like it a lot. The back country applications and the the ability to also use it as a car GPS is great.
The newer PN-40 looks to be a really neat machine--I also like the fact that with version 7.0 of the DeLorme maps you can buy a subscription for 29.95 a year for unlimited downloading of maps and other info...