Fast start sounds like fast glow to me. I made the mistake of trying a set of wellmans that would heat up in 5 seconds instead of 10 (I got them from MWFI thinking they were berus, but tried them anyway). Long story short, I have a rebuilt engine now. I have burned out a set of Beru plugs once when I had a bad glow plug controller and they all came out intact. The wellmans all lost their tips. Fast glow plugs don not impress me at all.
If you want to try a new glow plug type, than do a bench test and compare the results to a beru plug. Fail both plugs and see what happens.