I have been doing a lot of side questing but hit a point where I want to beat the main game before I continue my endless adventuring.

My question, is there any downside to beating the game before doing so? I saw some article on Forbes where the guy made a comment of how it was harder to find side quests after he beat the main game. Any truth to that?

Thanks for any help!

Some of the Faction Side Quests become locked or unavailable due to Faction War er sorry spoilerish answer there.

Its like trying to be in faction with Skyrims Stormcloaks and Imperails at the same time or FNV Ceasar and NCR at the same time...At some point with the main quest your locked into a faction or have to get standing with a faction to continue but other than that I don't know a lot cause I have just been exploring everything as I come across it haha.

Would I be forced to pick a faction and would I still get missions from them if so?

You can pursue quests for all factions up to a point. It's best this way though you won't be warned your going to become hostile to another faction until you get a fresh quest, though you'll know when you've done a handful of quests for any faction, and then just save before you go to hand each quest in. That way you can maximise the amount of quests you get access to.

Is this faction hostility thing tied to the main quest story? The first response I had made it sound like it was. I just want to be 100% sure before I decide if I want to beat the main game or wait longer.

Yes, but so is progress in the faction questlines, so avoiding the main quest wont allow you to finish the quest line for every faction, basically it is a unavoidable choice, you have to make a choice which faction you support.

Ok, I get it now. Thank you!

You can join all three of the factions, Institute, Railroad, and Brotherhood, once you're introduced to them in the main story, and becoming a full-fledged member will make you allied with them in the open world Commonwealth, even when they run into each other and start fighting each other, you can kill one of the faction's soldiers and still be allied with them; however, going to their bases and killing people there will turn them hostile. You will have to choose one of them in some way indirectly at the Battle of Bunker Hill, as even if you side with the Minutemen, they will be allied with the Railroad by default, and the other two factions will be eventually destroyed, locking you out of sidequests you can perform for them. But before that main quest point, you can do all of their sidequests as an informal operator for all three.
Note: If you're not strict about RPing, then joining all three ASAP is actually much preferable as you they won't fight back if you have to kill one of the faction's soldiers in the open world Commonwealth for a quest for another one of the factions. This could potentially turn the Battle of Bunker Hill into a leisurely show for you as you only have to watch them fight each other as none of them will attack you.

Fyi I have never done that battle quest yet I already reached a point with BoS triggering hostility with railroad as a quest START. That's why I warned you that you should save before starting your next faction quest if your worried about becoming hostile with one too soon. In any case this is several faction quests through.

So how does becoming hostile affect the seemingly infinite quests, like from Preston, those go away then?

I think Preston's quest still remain regardless of who you side with while you lose access to the radiant quests of the factions you killed in the MQ of your faction.

only downside is if you run through the main quest line to fast you can lock out certain things some of the factions can give you before you become enemies w/ them