The main thing to keep in mind when considering point buy numbers, is how is the rest of the world built?
In my campaigns, I give the PCs 28 points.
Normal people in my world are built on 15 points - 11, 10, 11, 10, 11 or 13, 12, 11, 10, 9, 8.
Above average people in my world may have 20 points.
Major characters (like heroes and villains) may have 25 points.
This means that the 28-point PCs are head and shoulders above the rest of the world.
Compare 14, 14, 14, 14, 10, 10 to 11, 11, 11, 10, 10, 10
or 16, 14, 14, 10, 10, 10 to 13, 12, 11, 10, 9, 8
or 18, 14, 10, 10, 10, 8 etc.
I played in a campaign once that gave the PCs 40 points! I thought this was over-the-top ridiculously powerful, but then discovered in play that the rest of the world were pretty much just like us. Every orc was a barbarian with full hit points. Every goblin was a warrior/rogue with full hit points. Every hobgoblin was a leveled fighter. Every kobold was a level 3 sorcerer. (Not kidding here -- *every* humanoid we encountered had class levels and full hit points.)
What at first seemed like a lot of power for the PCs turned out to be merely equal to the challenges of the world. Our party got its butt kicked all the time in that campaign.
The standard D&D game (right out of the books) is balanced on 25-28 point buy PCs.
Quasqueton