My wife and I moved down here 8 years ago. We live in the north-east and love the place. Here it is quiet apart from holiday season from Christmas to Easter. Apart from those times, I go for an hours walk on the beach and it is unusual to see, let alone pass anyone else. I haven't found the winters too cold and regularly go sailing in mid-winter with a 5 mill wetsuit and little else on.
Lifestyle here is very laid back. If you want a job, well that may be difficult. More employment available in the major centres of Launceston and Hobart.
As for the windsurfing, around here the prevailing wind which is a westerly comes across the mountains and is gusty. When we get the summer winds which are more from the north there is great sailing to be had, wave or flatwater. We have some of the best beaches in Australia down here, you won't believe them till you see them. Definitely no wave rage here, I sometimes even talk to the occasional kitesurfer.

Great year round sailing can be had in the Launceston region with good flat and waves. Westerlies there are across the water and are nice and steady.
To sum up, we would never even consider moving back to the mainland, never, never, never. For a start it would mean a divorce, no joke. Just a word of caution, we get people who shift to our town and they last around 12 months and are gone again, I think the call of the family can be strong, don't expect the rellies to come and visit you, it rarely happens.