From Jaster Mereel
1) Internal rechargeable battery: I’m a big fan of any device that sports a rechargeable battery. No need to continually sink money into traditional alkaline batteries or deal with the hassle of removable rechargeable batteries.
2) Size and Form Factor: Since this unit is basically an oversized watch, it’s ultra-portable and does not really stick out like a traditional handheld GPSr. The watch design comes in handy when caching in high muggle traffic areas as people pay much less attention to the guy looking at his watch.
3) WAAS enabled: Unlike the Forerunner models, the Foretrex is WAAS enabled which can help you get even closer to the cache site (and also helpful in acquiring more precise coordinates when hiding a cache).
1) Internal rechargeable battery: Depending on how you use your GPSr, the rechargeable battery may not work so well for you. If you regularly use your GPSr while away from an electrical outlet for more than 15 consecutive hours then this model is not for you. This problem can be overcome with the 101 model which uses 2 AAA batteries.
2) No mapping capability: Simply does not offer this functionality, although I think the screen is probably too small anyway.
3) Speed indication: My only real pet peeve of this units operation is that it cannot display speed in “mins per mile” unlike the Forerunner models. This will not effect your geocaching but when I take this unit out running I’d certainly like to know my pace without having to do the math.
It should be noted that some Foretrex and early-Forerunner users report problems with GPS signal reception due to the location of the antenna in the unit. While I have not really encountered this problem, one can reposition the unit on your wrist to better orient the built in antenna. The new Forerunner 205/305 has been redesigned to solve this problem, in addition to moving to SiRF technology.
All in all this unit offers basic GPSr functionality in a very small form factor; it’s like having a small eTrex strapped to your wrist.