We bought the Garmin Oregon 450 GB 1:50k at Cotswold Outdoors in the Cotswold Water Park. This purchase was made after considerable investigation and trial of other products.
Overall the GPS meets our needs for outdoor walking, geocaching and general outdoor activities. We even took it canoeing, mountain biking and to navigate in the car.
The Garmin GPS products are very good and this is no exception, but not perfect. This is our third Garmin device (an early non-mapping device, a GPS62st borrowed from work and this). Plus we've had Road Angel, Memory Map, PDAs and TomTom.
Garmin devices are very good for Geocaching as they can work with various websites, transfer cach information including descriptions, hint, recent finds etc. This is the main reason we bought another device. fast startup and GPS lock (few seconds), accurate positioning (often less than 10ft) with EGNOS, good battery life (although you'll need to purchase rechargables in the long term), robust, chunky to hold (but will take up a little more space than others in your pocket, and the original Garmin case is just too big), nice customisable menus. very usable.
It all synchronises with free basecamp software on your PC, and when connected runs from usb power rather than internal batteries if you setup to do that.
The slight negatives are the device doesn't come with a rechargable battery like other modern devices do (only the Garmin Colorado 600 series seems to have this). The chunky size is great to hold and use but still a bit thick for your pocket (the Colorado with 4" screen is HUGE). A 3" screen is just ok for 1:50k mapping (it's always a compromise with mapping between a usable size and how much can be displayed compared to a paper map).
Overall it is a very good handheld GPS for geocaching and fine for walking and outdoor activities.
We prefer the Memory Map ADV 3500 for walking (especially with 1:25k maps... the 3.5" screen is visibly fantastic but the touchscreen performance is very poor in usability)
We also liked the Garmin GPSMAP 62s which has a 2.8" screen but not a touchscreen. If you don't like touchscreens then I can recommend that as an alternative.
I probably give the Oregon 450 GB four and a half stars as 5 would imply it was perfect.
I think Cotswold should consider renting devices to customers so they could try several alternatives in real life before buying the one they find best. You'd probably have to pay the full price as a deposit but I would honestly do that. Until you have the device out in the wilds and try to use it for what you want you really don't know if it will suit you. For example I have to wear reading glasses and that makes quite a difference to the screens I can and cannot use without glasses. Devices with buttons are easier in those situation. But to see the maps clearly I always have to put glasses back on.
Thanks Cotswold.