I haven't had them long enough to confirm accuracy, but if they meet the claimed +/- 7 seconds a day, I'll be happy. This review is based on my (maybe flawed) assumption that they will last 15-20 years.
Assuming they perform as they should, the one negative is that they are a little large for my skinny wrist.
While I haven't own mine for too long, so far it has kept accurate time. I was also pleasantly surprised at how comfortable the strap is, much more so than the Swatch of my youth; it is very flexible and has almost a velvety softness to it.