It really depends on the way you like to play. Red Dots are great if you are fairly new to a weapon, they help you obtain your target much faster. Also, the cheapo 10$ red dot happens to be my favorite, although I would suggest you invest in something better than that. After a while, you can really get a natural feel for your airsoft guns trajectory, I used to use a scope to start with my G3, then I switched over to a red-dot, now I just eyeball it, and Ive never been more effective with it. After a while, you can just naturally feel where your fire is going to go. Iron sights are not an effective aiming device in airsoft however, airsoft guns just arent precise enough to utilize them. Red dots work much more effectively, and scopes should only be utilized with very high end guns. But like I said, once you get to the point where you can eyeball your fire, you wont be in need of any form of aiming device.