Trophies for me.  Leveling up and having distinguished categories is more appealing to me, it has more weight, like when you see a guy with a lot of plats you know they've completed a lot of games, if you see someone with a 10k gamerscore its like "they play a lot of games" you don't really get anything special for getting all achievements you know?

I think both are lacking:

gs lacks easy way to see how many certain person mastered since there's no diffrence in how many games you got them

trophies lack a total score to easily compare total progression beetween players

This.

each game on the 360 has 1000 gamer points.  trophies are the same but it is hidden a bit.  bronze is worth 1 point, silver 2 points, and so on.  i'm not sure off the top of my head how many points a game can get but  they are standardized just like on the 360.  

get enough points, gain a level.  the higher the level the more points needed (e.g. it is faster to go from 1 to 2 than from 10 to 11).  so to gain a level you can either get a crap load of bronze trophies or get half as many silvers.

Bronze - 1pt

Silver - 2pt

Gold - 6pt

Platinum - 12 pt

And yeah. the higher your lvl, the more points it takes to get to the next lvl. And with his breakdown in types of trophies you can tell between someone who finishes all his games. Or just plays a bunch without finishing it.

Trophies, as many have mentioned because of the bronze, silver, gold, platinum variety.  And i love the leveling system.  It feels like every PS3 owner is an RPG character and we're all leveling ourselves up.  Currently at lvl 11 (havent updated my sig)...got a long way to go before reaching that lvl 99 and being able to do 9999 attack damage lol.

The proportion is the same ... but the true points are:

Trophy Point Value
Bronze - 15
Silver - 30
Gold - 90
Platinum - 180

Level Point Requirements
Level 1 - 0
Level 2 - 210
Level 3 - 600
Level 4 - 1,200
Level 5 - 2,400
Level 6 - 4,000
Level 7 - 6,000
Level 8 - 8,000
Level 9 - 10,000
Level 10 - 12,000
Level 11 - 14,000
Level 12 - 16,000
Level 13 - 24,000
Level 14 - 32,000
Level 15 - 40,000
Level 16 - 48,000
Level 17 - 56,000
Level 18 - 64,000

And a game without DLC has about 1,200 points.

^_ Pretty much this. _^

I especially like the fact that by seeing a Platinium Trophy in yours or your friends' info, you get an immediate idea of how dedicated that person is to a particular game.  That, and the percentage next to the games' trophies he's doing can bring some friendly competition to the mix.  Like trying to  "out-percent" him. ^^,

i like trophies better because you have different lvls of trophies (bronze, silver, gold and platinum).