Confirmed by Bethesda:

To our fans who’ve asked: Fallout 4 doesn’t end when the main story is over and there is no level cap. You can keep playing and leveling.

— Bethesda Game Studios (@BethesdaStudios) August 6, 2015

On the other hand there are those that don't like the idea of over-powered characters. I remember some old-school Fallout fans who criticized that from F3.

They claimed that keeping a character unable to maximize all attributes and gain all Perks allows for replayabillity, as playing the game again and building up your character differently can make the experience more unique.

So it's like Skyrim, where you are technically leveling but you get less and less XP that you are practically not leveling anymore at some point.

Sounds good to me. I would like a new game plus over being able to keep play after the main story is done. Also I hope the loot or named weapons/gear is not leveled to the character.

So that means you get to be a god like in Skyrim. Doesn't really matter, I guess. Besides, for those who want things to be harder, there will be dozens and dozens of mods for that, including level cap mods.

Of course, godhood is automatically granted when you first pick up an anti-material rifle, anyway.

Godhood is a gift those vault dwellers will never have.

Catdamn it, those flies were bad enough, now they're bloody evolving?  Uncalled for.  Seriously, the only enemies in the game I didn't mind cheating to beat ...

fallout 4 is life.

And since it hasn't released yet, where are you? In limbo?

yes,like that south park episode,were cartman was waiting for the wii u. you might not get that reference,but that's what this is like. hahahaha!!!