Oooo....definitely strap comfort! You won't use it if it's uncomfortable to wear.

My Suunto has one of the nicest chest straps I've tried. Occasionally, I'll find myself still wearing it a couple of hours after a workout becasue I've forgotten that it's there. My older Timex was ok, but not "forget about it" comfortable.

I don't really use the whole zone thing and alarms. I'm lazy, I guess. I roughly know where I "blow up", so i'll check the display if I feel like I'm getting close to that HR and make adjustments to my effort to keep from "self-destructing".