Big difference is the noise. For all-out handling (race-track stuff), coilovers can't be beat. You get adjustability of ride height, it's easy to swap springs (for ones with different rates to alter under/oversteer) and you can even do corner weighting. Problem on the street is that the springs that give you great track handling are stiff as hell and not so comfy for normal driving. Also, most coilovers (maybe all?) eliminate the rubber in the upper strut mount which helps the handling but makes lots noise on the street - clunk, clunk, clunk over ever bump, pot hole, driveway, etc. For this reason, I decided against coilovers on this car.
If all you really want is a reasonable drop (say 1.5") and improved handling, then you'll probably be happy with a set of Eibachs, H&Rs, Esparils, or whatever everyone is recommending these days. Best appearance/performance mod for under $200.