With the next gen update fiasco do I want to let Galaxy installed FO4 or should I just install it via the offline downloads option?

If you already have the Galaxy version installed, just turn off updates and you're good to go.

Thank you. This is a brand new install so wanted to make sure I didn't get myself into a pickle.

If I were you and had 35 gig of free hard drive space to spare, I would 100% download the offline installer for FO4 ver 1.10.163.0. Once GoG gets the 'next gen' update. This version of the game will never be available to download again unless you grab it by "other" means.

While you can roll back the game version with GoG Galaxy, it only works if they don't patch the game ever again. If they push out 4 or so patches you will not be able to roll back to ver 1.10.163.0 as you can only rollback so many versions.

This 'next gen' patch really only benefitted the console versions. on the PC version with almost no benefits - yet?!

My experience with GoG Galaxy has been 50/50. There are times it worked great and then there are times it did not work. I disabled auto-updates for everything but one day it just decided it was going to patch [game] regardless of the settings.

I don't use Galaxy and install everything with the Off-line installers. Will the update be installed automatically? Is there any way to prevent it if you're not using Galaxy?

If you don't you Galaxy and you installed with the OFFLINE installers then you are safe. Your game will not auto update.
BUT if you decide to install Galaxy one day. It will detect your FO4 install and try to update it.

Great news, Thanks!

You can disable auto update per game or globally in Galaxy.