In the field...it has performed well. I purchased the OS 1.0 on Ebay last year after I read about Cateye upgrading them to 1.1. I sent mine in and got a brand new one back about 2 months later. The wait was due to the new models being shipped from Japan periodically and I had missed out on the latest supply. The new release added a time countdown option so you could set a specific time or mileage to start from.Setup is fairly easy but the statement of not needing a manual is not entirely correct. Without the manual you would not know the first step is to format the unit. It is menu driven but there are 4 buttons to work with. Once you set the time/date, tire size, and the speed scale is changed from Km to Miles, its ready to go. The standards are all here including speed, average & max, dual bike option, clock, elapsed time, & odometer. Probably the most useful extended feature is the variety of ways to view your ride data throughout the year. You can view mileage from your last ride, the last week, the month, and a bar graph of the entire year . There is also a place to add personal info such as your name, birthday, and mileage from your previous cyclometer. Like most other models you can customize the display for data that you want to see on the screen as well as the font size. This unit will wish you a happy birthday if you happen to ride on that day, which happend to me this past September. It also congratulated me at the first 100 and 1000 miles.