My In-Laws live in Rovaniemi so I can give some advice. Boblo may have been through in Summer and found it a little tacky, but that is missing the point somewhat as you are asking about it as a winter destination. Its worth a trip to 'Santa's Village' if you are in the area, but it is no more than a couple of hours entertainment including the obligatory reindeer or dog sled ride. You can also hire snow mobiles if the kids are a little older. Its pretty cool for the kids being able to send postcards from the post office in the village as well, which they can stamp themselves with the Arctic Circle watermark. If you are lucky there is a good chance you will see the Northern Lights, which are truly beautiful.
In terms of skiing, Rovaniemi and the surrounding area is ok for the odd day but is too far south to get proper elevation. The local resort is also notorious for only having 50% of its 6 (iirc) runs open. Pretty boring after an hour or two as the longest is about 600 metres long! You need to travel a couple of hours further north to get to the decent resorts really, but beware they can get very cold!
FWIW I would recommend a trip to Helsinki for a few days, then take a flight up to Rovaniemi for a couple of days which would be ample time. The village could be described as a 'little tacky' but to be honest its pretty hard to make something like that anything but a little tacky.