Hi, I have been a few years ago and will be going again soon, I didnt bother with the santa land type parks and hotels as whether you can get on the rides seems hit and miss, it is a long way to go and a lot of money to spend only to find its busy and you dont get on anything, so I went all inclusive and would do so again. The closer to Christmas the more expensive it is, Finland isnt cheap to start with.
It would be nice for the alpine countries to jump on this band wagon to cut down on flight time/ cost, but I havent found much yet.
The better day trips have everything laid on, no ques etc and you get everything laid on, the cheap ones drop you off at a park and pick you up later, you then pay and que for the rest.
What ever you plump for, the memories will be fantsastic (unless you get a cheapy one and end up all day in a que)