I dont think it makes agreat deal of differance if you have a high or low style one as either will get caught at some point It will make a differance as to what style light you use with them though, most go for the rectangular ones as they tend to be lower and because they are flat foilage will slide across them, i have round ones and have had no problems with them at all.
I think it is just personal choice
Also dont forget that rrc/defender light bars will also fit the disco , i have a defender one on mine