I do most of my fun work with lightning Lap products. The only metal laps that I use any more are coarse toppers (180, 260, 320 or 360) After using the coarse metal laps I do the rest of the facets with D-Lite laps starting with the 325, which actually leaves a surface that is similar to a 600 metal lap and then on to a D-Lite 600 which leaves a surface similar to a 1200 metal lap and then the D-Lite 1200 which leaves a surface similar to a 3000 metal lap. I then go on to polish from there. Plus to save money all of these laps are toppers.
I have been using these laps for about 3 years now and I am definitely a believer. One of the great things about them is that when they seem to loose their aggressiveness or when they seem to be leaving scratches, I can refresh the lap surface by wrapping a piece of wet/dry sand paper (400, 600, or 800 grit) around a block of wood, then turn the lap on and give it plenty of water, while I gently drag the sand paper across the lap. When the water turns the color of the lap remove the sand paper and rinse the lap thoroughly and you basically have a brand new surface.
If he lap ever wares out, send it back to the manufacturer and he will send you a new one at a discounted price. I have not yet warn one out, but I had one where the grit became delaminated and the manufacturer sent me a replacement for no charge.
These are great laps and I know several people who use them to cut competition stones.
I highly recommend them.