I have around 20 GURPS books from the old system(before they made it way more streamlined).
I've played many a GURPS game(although not recently).
The upside is: there are rules for everything, and these rules makes sense within the physical realm. i dare you! make me any sort of weird scenario and i can find the rules.
Downside is: there are rules for everything! so much dice rolling and looking up tables and generally doing maths.
a good example, that both contains the strength and weakness of the system:
To shoot somebody with an arrow you have to either spend 2 turns drawing and knocking it, unless you make a quickdraw(arrow) roll.
Then you have to determin the range to the target, the speed of the target, your own speed and the size of your target, then subtract point for targeting specific body parts. Then you add accuracy bonus from the weapon.
now add all these modifiers to your Bow skill and roll 3 dice. If the roll is below or equal to your modified skill you succeed in shooting the guy.
now you gotta roll to see where you hit him(unless you were shooting fora specific body part)
Then you roll damage according to your str plus damage bonus from the bow(or magic bonus) and subtract Damage Resistance(armor)
Then you have to determine what Piercing(arrows are piercing) does to the bodypart hit, and how damaged the body part really is, is it still usable, badly damaged or do you get a blow-through.
now i'm getting tired of writing this, but there is a bunch of rolls to determine what happens to the guy if you hit.
I hope you get a sense of the game from this: it's an almost scientific approach to Roleplaying.