I’ve been spending some time on the trail with my Garmin Colorado 300 and have been testing it against the Garmin 60CSx. Some folks have asked questions about satellite reception, since the Colorado reportedly uses a proprietary chipset and not the SiRFstar III found in the 60CSx. The image above compares tracklogs from both for the same mountain bike ride. Topography was steep in places, with canopy varying from deciduous trees to some mixed evergreens. Not the most difficult conditions but challenging enough that older receivers would likely have dropped out numerous times.
The yellow is the Colorado 300; the blue is the 60CSx. Notice that the tracks separate in the SW corner. I had a previous track of the same ride collected with the 60CSx, and that one is layered on in what Garmin calls magenta (i.e., pink) below.
It appears from this that the 60CSx was more accurate, but notice that the older 60CSx track veers away from the other two in the NE corner, so I wouldn’t draw too quick of a conclusion. The two images above can be clicked for a more detailed view, BTW.
Digging a little deeper, we see that the Colorado did more wandering at a point where I got off the bike for a snack, as shown below in this detail near the SW corner.
Both devices’ tracklogs wandered around the trailhead near the NE corner of the ride.
One other interesting thing. Both devices were on my handlebars at the start of the ride. Midway through though (shortly after the SW snack I believe), I gave up on the Colorado mount and put it in the outside mesh pocket of my CamelBak. This may have been a slightly more challenging position for reception than being on the handlebars.
I’m not sure you can draw a definitive conclusion from this, but I feel like I’m only going out on a limb a little to say that these are both excellent devices and that you will likely see very little difference in reception performance between them.