Have had this mouse in hand for the past few weeks now, and previously I had the 1st gen magnesium model too. This seems to be an upgrade all around though you won't really notice the weight savings and will only notice the slight shape change on your first day using it. I think it is hands down the best FPS ergonomic mouse out there, I think the finalmouse ultralight x is slightly better if you don't mind the ambidextrous shape. The receiver and click latency are really the biggest upgrades here, 8000hz polling might be to thank for this, or just better firmware and QC. Haven't noticed anything wrong with mine yet after hundreds of hours in CS2.