Well, since I have both, and have been using the Garmin for a full week now, Ill try to post a good comparison soon. For now, Ill stay away from two things: 1. the fact that the X10 is 100m water resistant, and the Garmin is not for swimming. 2. the fact that the Garmin is primarily a HR watch, and the X10 has no such functions for 'workouts' but is meant as an advanced ABC outdoor watch.
Ill focus just on things they compete at which is GPS. For now, Ive noticed the following which the Garmin exceeds at:
1. GPS reception - although both track about the same once satellites are acquired, the Garmin gets a fix with a 5 meter position error in about 20 seconds...no kidding.
2. Navigation - the Garmin, as a full dot matrix screen much like the X10, relays much better information. For example, when doing a 'Back to home', there is an ARROW that comes up superimposed over a floating compass, and on screen text prompts give you warnings, like 'Right turn coming up'.
3. Courses - as long as I have had an X9 and X10, I have not been able to upload tracks to it. I can save a track, and use it again, but I have not been able to upload a track from another site. Garmin Connect is pretty cool. Its a great place to download rides/runs and it will automatically load into Google Earth (unlike the X10 where you have two places...Track Manager and Track Exporter to Google Earth). Garmin Connect you can also look up other peoples runs/rides and upload those routes to the 405cx really easily. You can also compete against thier times if you are interested. Although the Garmin has a screen that will tell you Time to location, Time Enroute and then compare it to previous or other peoples routes, I do like the X10 better here for Navigation as it has an Estimated Time of Arrival. I know I can do some math, but Suunto ads a nice touch.
4. Both have Sunrise - Sunset times.
5. When you first get the watch, to set time, date, sunrise, sunset etc on the Garmin to your current location, you just have to, ummm...turn on the GPS. No setting UTM data, GMT, etc etc...just simply turn on the GPS once the battery is first charged.
6. The Garmin tracks altitude as effectively as my X6HRM on long rides, which is an improvement for a GPS watch. The Garmin also does a couple of other cool GPS things: ongoing direction based on compass pointers and % grade of slope. With my X6, I definitely have to stop to get a slope reading.
Thats the basics of it. The Garmin is definitely slicker. The X10 is definitely tougher. Like I said, two different purposes for each, but the bare bones GPS navigation function I would have to give the nod to Garmin...probably because that is their thing.
I wouldnt wear the Garmin all the time though. I emailed Garmin support and asked them what the bezel and crystal were made of, and got the wierdest answer: Unfortunately the material and crystal are proprietary information.. However what I can tell you is that the bezel is heat sensitive and not touch sensitive. I hate stupid stuff like that. Maybe Garmin is run by extra-terrestrials....
Bottom line: I wouldnt take my Garmin hardcore camping or hiking because I would likely forget to take it off for swimming etc...although I would likely take my bike camping...and my runners...for workouts...so guess I would take both.
I really hope the NEW SUUNTO coming out is a GPS enabled workout watch that is 100 meters water proof and as tough as the X10 with all of the ABC functions too!....oh ya, and can make coffee, right Jeff??