Strengths: It doesn't take long to get a signal - 1 minute or so. I don't use all the features - only time/distance and pace, but it gives an accurate reading. Doesn't irritate my wrist (I changed straps to the velcro option). Battery life is reasonable - I get 3-4 runs before I choose to recharge - which takes about 10 to 15 minutes.
Weaknesses: Doesn't like moisture (rain or sweat). I now wear it over a thin wrist sweatband which seems to help. When wet, it changes screens but still always stores the run information.
Overall: Fairly satisfied - although not perfect. Occasionally frustrating, but not to the extent that it malfunctions. No repairs etc. needed so far. All in all acceptable. Looks a lot better than the 305, the size of which put me off.
Weaknesses: Looks like they might not be the most durable pair of running shoes.
Overall: Having suffered with calf soreness while I was wearing the Kayano 16, I was persuaded to buy the Brooks Ravenna. I was advised that I didn't perhaps need the level of support that the Kayano were providing. Two weeks into using the Ravenna, the calf soreness has improved significantly. I am now more confident stepping up the miles for the Liverpool Marathon in October.