Well, I "won". Not 100% completion, but beat the main storyline.
So I figured I would give my score card.
Missions - grade B; Some were better than others. I felt the game provided maybe too many learning missions. More variety is always welcome. I still feel Vice City set the standard for fun and creative missions, but of course after you have played GTA III, Vice, Liberty City Stories and San Andreas the GTA formula is going to start to feel less original. I was impressed with some of the in mission scripting, that happens during some chases with stategic cars coming in a certain way to create certain crashes. I like that kind of thing a lot.
Controls - grade A (driving); D (on foot); Driving controls were the best yet. When I compare them to trying to drive in Vice City using the PS2 accelerator button, or even San Andreas, they are perfect. Good cars handle good, bad cars handle bad, and speed control was an absolute joy! As usual the on foot controls were clunky, and at time manuverability in combat situtations was tricky. Manuverability in the weapons shop was horrible. I applaud the addition of a cover system, but it was awkward at times.
Graphics - B; Admittedly, they did not blow me away, but they did not really dissapoint. Rhere's a mission on a cargo ship, where they really did this amazing detail work; there's a pizza in the ship's kitchen that looks exactly like you would expect a pizza to look like. There are asphalt roads were you can see the brick work underneath where the asphalt has worn, just like you would see in real life sometimes. There were cool graphics variations in cars, such as rusted out versions.
Goodies - C; Where's the RC missions ? I have not found them yet in any case. No rampages, I guess I can live with. They spent 100 mil on this game supposedly, but there seem to be fewer side missions/games. No arena, no RC missions, no rampages, no property buying. I miss them.
Dialog/story line - ?; Not sure what to think. Too many bosses, Niko always felt like a pawn. I was looking for a little more innovation. The characters Niko worked with never felt likable. Most were annoying. This is highly subjective though.
Weapons - A; Nothing new, but everything you needed. Auto aim and free aim were both great.
Cars - B; Great handling, nice details, could shoot out tires etc. But no innovation over previous games. Not enough motorcycles on the map for quick use when you find a ramp. You should be able to buy cars, IMHO.
Radio/TV stations - grade B; The radio stations were great musically, especially Liberty Rock. They chose some great songs, and a lot of variety. Commercials were ok. Talk shows were not really innovative. The TV shows were really well done, but why would they spend money on something that did not happen during game play? I would have rather they put that money into cooler missions and such.
Difficulty - grade B+; There was really only one mission I thought maybe was a bit too hard. My nephew stepped in after I got stomped quite a few times on it, but I am sure I could have done it with enough patience. Some missions were surprisingly easy. I would say only five were hard, making this perhaps the easiest GTA ever. In part the ease was due to the new evasion system and the amazing driving control. It was much easier to maintain control. The cover system helped a lot too in making some missions pretty easy. Of course ammo was easy to get ahold of, I remember running out a lot more in previous GTAs. I like games you don't have to retry missions 20 times. So I am ok with the overall difficulty level reduction. Perhaps a few more slightly harder missions

Overall - B; I give it a B because I LOVE the GTA series and they did not screw it up. My main complaints were some on foot movement annoyances, lack of mission variety and the lack of RC missions or some other cool side missions. I enjoyed beating it and will probably play longer, to do the races and such. I don't think you can go wrong buying this game if you are a fan.