This may be a little late…
The Forerunner 210 is a solid option from Garmin. Its market niche is for the runner who really does not want/need to customize their GPS device; so, there is little in the way of customizations that the user can do. Though the screens seem to be well thought out and give most folks the information they need; just possibly not in the order they would like. The unit is quick to learn and ready to go right out of the plastic (err box). It is reportedly very accurate with its state of the marketplace antenna. For most activity, I think this a great unit.
A word of note for the Galloway folks. This is not the unit I would recommend for a marathon (half OK). Unless there has been a firmware revision that I have not seen, you are limited to 99 intervals. That would mean one would possibly need to stop and restart the interval function if they were a 15 minute runner and using a 3/1 (or more frequent walk) interval. The math I used would have the interval stopping at about 1:40 for a 30/30 runner; 3:18 for a 1/1; 4:57 for a 2/1; and 6:36 for a 3/1. I have a couple folks who do not mind stopping and restarting their interval timer mid run but I am one who does not want that mess. If a continuous interval function is important and you, I would go with the 610. Also, as mentioned above, the 610 has a vibrate feature that one can turn on or off.
Though in my last marathon I was a good 90 minutes off pace and found that my 610’s battery failed around 6 hours into the race with both the alarm and vibrate functions on. Admittedly, the battery did fail altogether a couple weeks later so it could have been a one off issue.
A word on RunKeeper/Nike or any other cell phone based app. These are nice apps and in general work well. I have run with RunKeeper in my ear during a few races – more for its ability to post my position live online than for pacing. My crew can then follow me on line and start to look up road once they start to see that I am within a half mile or so of their position. From an accuracy viewpoint, these are not very accurate. Their accuracy is only as good as the cell coverage in the area of the run. The general standard of accuracy for a GPS device is about 10 feet, a cell based device can vary from 10 feet up to a couple hundred feet depending on the ability to triangulate off towers in the area. For many folks this is good enough. I just find that the inconsistency of positioning can create a reported pace that jumps around much more than it should. One issue that many folks have with these apps is the battery life of the smart phone. Simply turn off the 3/4G, wifi and Bluetooth antennas and the phone’s battery will last a full marathon or longer.
Hope this helps