I do, to an extent, regret not going down to the Gothenburg Book Fair myself this year. But I can't really afford it as I am not part of any money-generating machine that will pay my hotel bills, etc. Besides, I have to become more aware of what's worthwhile on the Swedish and Scandinavian literary scene. But I may very well attend next year.
You have to plan well beforehand, otherwise you can get book fair burn-out and spend your time sitting in a pub far from the venue and taking walks in the fresh air (Gothenburg is an attractive city). So unless you have a stand of your own for your publishing house, a book fair involves a lot of trudging about and picking up visiting cards and leaflets to put into an increasingly heavy bag. And chatting to people who have another 25 to get through the same day so that by six o'clock the meetings merge in their minds.
The big advantage is that you meet some of these people eye-to-eye instead of only email-to-email. They might even remember you. Translators especially need to remind publishers that they exist.
But a book fair is, in theory, different to a book festival. The former is very much a buying-and-selling enterprise, with seminars and talks attached; whereas a book festival, in theory at least, is more of a book-examining and book-reading event. But I'm sure that the distinctions are blurred a lot in real life.
One thing that looks interesting at Gothenburg is the fact that several author's societies (litter?ra s?llskap) have stands there. So if you're interested in a particular author, you can join the society and attend regular meetings, assuming you live within hailing distance of the regular venue.
They do try to cram in an awful lot. For instance, when speakers only have 15 minutes to say their piece, and as we all know, modern man (and woman) cannot keep to the clock, so there will be a number of disappointed people. In my opinion, you need at least 25 minutes, plus five for questions, to do justice to any subject. Otherwise it becomes a matter of going through the motions (pace Andrew). And parallel sessions means that it looks good on paper, but in real life you have to miss a great deal.