I used the suction mount for a bit, then switched to the 3m stick on mounts.
I tethered that, but after a while stopped tethering it because the 3m stuck so well.
Also had a screw in mount, looked similar to this, but never installed it, still have two of them.
Currently I'm using the ram mount on my handlebars, which IMO is the most secure of all, the downside is it only show's whats in front of you.
here's a pic of dual ram mounts, which is how I have it set up now... Left mount holds gps, right mount holds phone (navigation) but can be swapped to the gopro in about 15 seconds.
side view, what I like about the RAM is that you can change the position to suit your needs, and if you have a mount installed on more than one ski, we had 4 ski's and we all had the same mount, then you can swap the camera from one ski to the next in seconds.
I typically ride with gps/gopro mounted and the phone in the glove box, and swap out if I feel the need, and when I'm ideling, or even just going slow, I can remove the ram connector with my left hand and remove the gopro for handheld use, when I want to speed up and need both hands I can just pop the gopro back in the glove box or shove it inside my life jacket for a few minutes.
the only downside i've found with handlebar mounts is the limited view it provides, generally produces what my wife considers extremely boring video's of tree's and water.
I have several spare mounts that I purchased over time, but they just sit in the box, if somebody is interested in a couple, I can hook you up pretty cheap.