I have used an Exp 400 for about 2 months now and it fits the bill for me. I prefer the mono screen because it is easier to see in bright sunlight than color screens I have used. Also, I visit cache locations all over the country, and it is really simple to file each set of caches (and detail maps for that matter) on the SD card. In my limited experience with Gekos, Garmins, Sportraks, and Explorists, the sportraks and explorists acquire and maintain satellite signals better in cluttered terrain. You will find others that will strongly disagree, of course.
With the lithium-ion battery fully charged, I can do 3 days of caching (3 hours at a time) and still have half a charge left.
Your preferences are unique, and that's why there are so many kinds of GPSrs. Play around with as many units as you can, and you will find one or two you are most comfortable with. I was able to buy a unit on Ebay, try it out, and then sell it for what I bought it for if it didn't meet my purpose. Just my 2 cents.