Depends what you want. Its about one-third the size of the London show, and has a limited range of chandlers etc. but just about covers the bases.
The one good thing is that they arrange all the yachts at one end of the hall, and the motor boats at the other. They back the boats into a rasied area so you can walk around and see them all from deck level, which is a boon. Also, unlike London, you dont have to queue to get to crawl on them.
If you are in Stockholm, or want something particularly Swedish, then go, otherwise, dont bother (IMHO)