I thought the notification feature was a gimmick when I bought my F3, they put it in there so they can put another bullet point on the feature list. I want an exercise watch! But it's worth having. I get home, I set my phone down, and when somebody calls or messages me I don't have to go find it to know why. Sometimes when I car pool it's very valuable to get messages in the shower.

On that note, the watch will also vibrate on your wrist and chime if you want it to for anything you put in your calendar. My memory isn't getting better as I age, so this is very good for me.

You should definitely use a chest strap, it'll be more accurate and Garmins tend to to give you more accurate calorie info from a chest strap. Mine has the wrist sensor but I use a chest strap on the bike (except when I forget, then I'm glad to have the wrist one as a backup).

My strap broke after about a year and a half. Right where I clasp it. It started to crack, and over a couple days the crack grew across most of the strap, I replaced it before it failed and I lost the watch. I would guess that taking it on and off every time you ride would put a lot more stress on the strap and cause it to fail more quickly. If you decide to do that, please check your strap regularly because if it falls off the bike during a ride you might not be able to retrieve it.

Final note, I also hike, and occasionally I swim in lakes in the summer, sometimes I run. I really like having a good fitness watch with me at all times. Very much.