I can answer some of it now. The rest will be from more experience with it.

Are you wearing it all the time, or just for exercising? I will be wearing it to exercise only. But one could wear it non-stop as a regular watch or to have their heart rate monitored all the time (that is until the batterie needs recharging).

Does it beep or make noise? (Is it possible to turn this off?) If you set it on exercise, it can notify you by beeping once when you are not exercising in your target heart rate zone. A double-beep indicates your heart rate is 10 BPM or more outside the target zone. But for the beep to work, you need to set the timer at "on". At least this seems to be what I experienced so far. If the timer (chrono) is not on, you will see lights flashing indicating what level you are exercising into.

Are you using it together with an app? Which one? Does it work well, or is there a delay or gaps in the data transfer? Not yet, info to come but it will be with either an iphone or ipad.

Have you had any experience with water? (Swimming!?) - I'm not going to use it in water so won't be able to help.

How often do you have to recharge it? I don't know yet. More to come. But the user's manual says in exercise mode it should be good from 8-10 hours. Don't know how long charging takes either. Nothing says in manual (I think). So I'll check that. Yesterday for the 1st full charge on usb plug it took about 1.5h.

Is the only difference between the "alpha" and the "link" the display? Why did you choose the alpha? There are a few differences but I chose the Alpha because I wanted to see data on the display. Not just a colour coded blinker. Will also be useful when doing other activities that will not be "hooked" to a phone or tablet. So I can run without having to look at a phone. But it does suck the life of the batterie quicker than the Mio link.