I believe that the paddles and blades are the most important parts to heli in terms of affecting the way it flies. Don't cheap out on paddles, get a few different sets. They all fly differently and when you find a pair that fits your style it's like wearing your favorite shoes. Ok, enough with the clothing references. This isn't "what not to wear". Thanks to my wife I now know the name of that awful show. But I degrease
These little thing are half of the heli's control so it is a good idea to get a grip on what makes a good set. I first thought that lighter is better when trying to make the heli quicker. I had a set of home made carbon paddles that had to weigh about 10 grams. I had to dial in expo and thing was all over the place in forward flight. It rolled like a profile though. So the first factor is weight. Stock black raptor 50 paddles weigh in at around 25+ grams. In sequence of slowest to quickest for the Thunder Tiger Raptor 30/50 paddles are black, white, and green. The blacks are great for learning as they make the heli super stable. The whites are the middle of the road weighing in at 20g. The greens are the lightest at 17g. I love the green for my style of flying(stick banger).
The next important thing to take into consideration is the length, more surface yada yada you guys know how this works. The last thing to consider is shape. While the green paddles are the quickest of the group because they are light, they are also have a very thin leading edge. This knifelike shape gives it the bite, but also makes it a little "pitchier" when in fast forward flight. For some reason this doesn't seem to affect underslung head heli's as much as it does the raptor. There are some factor that affect the carbon paddles made by V blades, Mah, and the others. It has to do with how far off the flybar they place the weight in the paddle.