Installed my Polini last weekend, and I'm really happy with it. The 6.9g rollers that come with it weren't to my liking, but that was expected. Once I put the 6g Dr. Pulley sliders in, I think I'll be very happy.
The difference for me when choosing was $ and what came with the kit. Dr. Pulley too expensive for what you got with it Malossi maybe cost slightly less than Polini, but again that was without rollers.
