GURPS has a reputation of being overly complex. The problem mostly due to the core books becoming more of a toolkit making it difficult for novices or gamers coming over from other system to figure out how to use the game. GURPS 2nd Edition (which I started) it was easy for AD&D players to understand how the system worked for them. The core set + GURPS Magic was a inexpensive investment for a near complete Fantasy RPG. GURPS 4th edition is actually a better system. Whatever issues I have about the presentation in the art of rule design the folks at SJ Games are top notch.
Anyway enough of the complaints.
GURPS is a point based system. Most GURPS 4th edition campaign start out around 150 total points. This produces a competent character compared to a 5th level character in various editions of D&D. If you want to start a true beginner then 75 to 100 points will do it.
A GURPS characters has four attributes Strength, Dexterity, IQ, and Health. There are four sub attributes based off of the four. Perception, Fatigue, Will, and Hit Points. It is rare to vary these from their base attribute.
You also have Advantage, Disadvantages, Quirks and Perks.
Advantages are things like Combat Reflexes, Magery (needed to cast spells), Social Level, etc. Disadvantage are mental or physical limtations of your character. They included positive disadvantage like Honesty, Code of Honor, as well as the more obvious hindering ones like one handed etc. A typical GURPS fantasy campaign will allow you take up 40 points worth of disadvantages. Disadvantages give you bonus points to spend.
Quirks are 1 point disadvantage. They you use them to define well ... quirks about your character. Like "Always sit with his back to the wall.", "Doesn't like the color red." You typically five of these. Most GURPS GM I know only ask to define 3 and letting the other 2 be defined during the first few sessions.
Perks are 1 points advantages. Little benefits you can buy. Like Alcohol Tolerance, Deep Sleeper, Honest Face, etc.
Typically you wind up spending around 195 points as a starting character.
The reason I and my group like the system is that we have control over the characters we create. My point of view is that the uncertainty of the campaign is good enough for me and I like having control over where I start out.
GURPS 4th edition deals with the diversity of choices by offering templates to use for character creation. These are packages of Attributes, Advantages, etc that allow you to make a character of that type. Some are professions, other represent classic roles like Fighter and Thief. GURPS Dungeon Fantasy has a bunch of these for D&D style adventures. GURPS Fantasy has more still oriented towards more toward a low Fantasy Realism.
GURPS Lite is free and provides a good overview of the system. You can find it here.
The 3rd edition version has a small taste of the magic system and you can find it here.