I replaced the 5" headlight on my Scrambler with a convex Cibie 7" headlight (needed a bigger bucket, of course). The difference is amazing. The stock headlight was absolute crap (the ST3 headlights are way better), but the Cibie throws out a hell of a lot of light. I don't feel the need to upgrade the ST3 headlights, but if I did, it would be with the Cibies.
In this shot, you can see that its really not too convex: