Well my 2 cents I prefer forums for most things. I was a slow adopter of Facebook I honestly held out for a long time but around the time I started my business I more less had to have a Facebook account and run that side of things. But it all comes down to what does what best. Facebook I think is great for keeping up with people and friends that I don't get to see often. I think it's about the worst platform possible when it comes to finding old information. I would compare it to fishing, if what your looking for is going by at the moment, great. If not good luck searching or finding it after the fact. That's my biggest complaint, just too dang hard to index after the fact which leads to repeating information more often than forums. The second biggest complaint is no categories or way to create them. For instance if I go on the MIA Facebook I have to weed through sale posts and everything else just to find actual questions or information. I can't just browse one topic, I'm browsing the entire group of possible topics which if I don't have allot of time to invest makes for a frustrating experience. Casual questions and chat like interactions I think is where Facebook excels, it's quick and easy for that sort of thing. It's very good cross platforms compared to forums, even with Tapatalk forums are more difficult to navigate(latest updates to Tapatalk interface have made this worse in my opinion as well). So I'm not knocking Facebook, it is what it is, but their expansion into groups and whatnot I think is not working to it's advantages at best, and at worst it's working within another walled garden where they could shut things down in an instant with no recourse. IE just like what we left behind with Proboards, if tomorrow Facebook decided that replica firearms violate their TOS then there goes all of those groups. It's happened on other platforms and will likely continue because we're related to firearms and that is a hot button topic among allot of people, particularly people from the west coast where most of these companies operate from.
So forums to me give more freedom, much better indexing especially when able to use google to index like most forums allow. I can't tell you how many times I'm doing domain based google searches looking for some old piece of information. Proboards worked with that, but I'll say I believe something was screwy in their way they allowed indexing as well. I had trouble in the past getting google to pull results that I knew existed. But I use that function on a ton of forums related to non-airsoft topics as well. So overall I think forums are a better platform for a hobby like airsoft to keep the information in one place that is easy to pull information back as needed from the backlog of history. The one thing I don't care for with forums is the speed of access and the method used for posting. It's much slower and more deliberate than Facebook in the sense that you need to put the post in a specific area, as well as name the topic. It's less lazy, maybe that's a good thing it could be argued either way. But overall I prefer the semi formality of the forum based system, along with the organization and indexing.
I'm a part of a holster maker group on Facebook which also has a forum which honestly hasn't really taken off. But we have a ton of great information on making holsters, tons of useful info. Allot of it is lost to the Facebook system. I've seen time and time again guys ask the same questions because they flat out can't find the older information. I've gone looking several times for things I know were posted say a year ago, can't find it. Once in a while I get lucky but often I come up without anything. To the point that I will search my email for a notification on a topic from a year ago, use the link to pull the URL on Facebook because it's faster. That sucks.
I know allot of guys particularly it seems younger guys really seem to like the way Facebook handles information for me it's a chore often times despite how much time I spend on there. So I think they both have their own niche benefits but forums are much more functional. If I could only pick one or the other it would be forums all day long.
Luke
EDIT: I forgot to mention I'm on just about all of the airsoft related forums and have been for years. Some of them I only lurk on, actually I'd say most. Like Arnies, I read there often but seldom post. Airsoft Sniper Forum, I read allot and post once in a while when it's something I've got input on. Some of the newer forums like Airsoft Forum, I read but don't post, Airsoft Mechanics is about the same. More less I search and index all of them but seldom post. MIA, and ASF are the two I spend the most time reading and posting on. But I'm also involved in several firearms and holster forums some of which I sponsor which take up allot more of my reading and time.