Strengths: Not only does it give a measure of distance it gives a better measurement of pace than my Polar S625x. I find this is invaluable when doing tempo runs. You can use the virtual partner, but I like to see the numbers and actual time. You cannot see these with the virtual partner. The ability to record lap time automatically is also brilliant. I record mile laps on long runs and compare each mile at the end of the run. It is very easy to switch between miles and kilometers. I use this when doing a few miles warm up and then doing speed work over metric distances. This is a useful tool for me as I do all my speed work on the beach. The rechargeable battery is a godsend.
Weaknesses: Any trees can be a problem for the 201. If, when recording automatic mile lap times, you lose the GPS satelites it can give you inaccurate times for each mile. I did have a problem in being able to download the data from the unit to my new PC. The connection is for a serial port but I did not have a serial port on my computer. This was overcome by purchasing a serial to USB cable and after some fiddling was able to download the data.
Overall: I bought my 201 last June and I must say I love this piece of equipment as much as my Polar S625x. Not only have I used it on walks, I have even used it to measure the distance between two points on the golf course. This now further extends its range of use, especially now they have made it legal to use a GPS on the golf course. I might even improve my golf handicap.
Strengths: Not only is this a good tool to measure your speed and distance, it is also excellent at measuring your improvement over time. I have found this to my benefit over the last year. This is can be seen with the OwnOptimizer, fitness test and Recovery measure. OwnOptizer tests your HR at rest and when standing and compares it with previous readings. It then tells you whether you should go out on that hard run or change to an easy session. The same as your body is telling. I love it as an excuse for not doing those dreaded tempo runs. The fitness test can be carried out every couple of weeks and is a measure of your Vo2max. As your fitness improves so should your vo2max. The Recovery measure takes your heart rate at the end of the excercise and then again two minutes later. The drop in HR should be quicker as you improve over time. I use this after every training excercise and it is a real motivator for the next run.
Weaknesses: The Altitude and ascent reading are not alway accurate. Having said that these do not bother me as I do not use them as part of my training records. However this may be of some concern to fell runners. Distance measurement was inaccurate initially but after a manual adjustment I managed to get it within 1% accuracy. Good enough for me. It does vary slightly on different runs but so does my Garmin. The food pod does use batteries quite quickly and I have had problems where the battery seems to run out a lot quicker after the pod has got wet from a beach run. I am beginning to record the time between battery replacement to confirm or disprove this comment.
Overall: Although I have not given all 625 reasons to buy this piece of equipment, I have to say I love the information it gives me. This is a very powerful tool and a must for data seekers if you are patient enough to sit down and read the manual and you like to vary your training. If you are a person who likes a simple life then this is may not be the best for you. But if you dont buy one you will never know what you are missing.