The best option is to wait until after the guide comes out so you can get some feedback on how useful it is. Although with Fallout wikia, I don't see the point of getting a strategy guide. It is not like we are in the 90s where sites like gamefaqs are non-existent.
I'd say yes.. Oblivion, F3, NV, Skyrim all had excellent guides. They've become really good at making guides for these massive open world games.. (Morrowind's guide is quite horrible in comparison to the more recent guides.) There's usually a lot of info in there that you don't find out in game. Plus,... maps! I never use the guide for getting me through quests or missions... but the maps are invaluable for me to pick my exploration path. If you're the type that plays simply for story.. you probably don't need a guide. If you plan on doing every single thing there is to do, you'll definitely need a guide. You can however wait and all that info will eventually be easily found on the internet but it takes a few months for it all to be there.
I only buy strategy guides for collecting, I never use them as I like to play the game blind with no help. Though, I did find Skyrim's hardcover guide interesting as it was the artbook as well.
Lol, just get it. If you enjoyed the Skyrim guide then you will like the Fallout 4 guide. There was no reason to get a GTA5 guide because the game is pretty straight forward.
For me strategy guide are now more for collecting. I usually use the internet more than the start guides but hey love supporting the company. Funny though the amount of work going in a game and paying $60 (at the time) and then half that for a start guide which takes what 10% or less of making the game but costing half the game seems a bit too much, but again love supporting Bethesda.
I loved the Skyrim hardcover CE guide. I didn't read the sections about quests as I didn't want to spoil anything, but it was fun to have a sort of companion book with interesting details about gameplay features.
Also when making mods, it was helpful to have a reference for some of the details about various actor types and objects. I think Prima did a fantastic job.
I loved, LOVE the Witcher 3 Deluxe Strategy Guide. I hope Fallout 4 follows suit with all the goodies we got with that.
prolly going to get it as bathroom reading material other than that will use online guides