This is just my opinion...you decide for yourself:
I installed a HiViz fiberoptic front sight on my Glock 22. It included 3 orange and 3 green light pipes of different diameters. I like the sight very much for a range/plinking gun or for IDPA. Basically, I feel that the light pipes are a bit fragile for a carry gun; I had one snap in two.
As far as providing a highly visible front sight when a light source is available, they are wonderful.
I'm not aware of them being offered in different heights.