I've been playing tabletop games for about... 12 years now, I think. 
For new players, Pathfinder is often harder to get a grasp on, if they've never used the d20 system before. PF is essentially an updated version of D&D 3rd Edition. It's better for people who are already familiar with d20 mechanics, as the transition is pretty smooth.

5th ed D&D is very new-player-friendly. I've been play-testing it since it's initial release, and the rules are much less bulky than pathfinder, though you do incur a greater cost in book resources as Ellri mentioned.

But, if you just want 1 book, a simple rules systems, and an interesting setting, look up Numenera. It promotes more roleplaying and less [i]roll[/i]-playing, and combat doesn't takes an hour or more to complete (like Pathfiner/D&D); in fact, you can run through 3-5 combats in one session and still have time leftover to explore, discover new things, and roleplay with NPCs. Streamlined mechanics makes things easier as GM and as a player.