I got one, it's mighty nice. Holding it in one hand and 725 in the other they feel the same... The 1.x pound difference isn't really noticeable. However there are things that are noticeable to be.
-it feels way more balanced in your hand. Like the weight seems more centered over the top of your hand, it is less fatiguing as a result.
-the hammer action is more muted. Whether that is a result of the construction damping the noise or increased power reducing hammer action, it is significant. Taking off even real tight lug nuts it just sounds like a drill removing them, no banging unless something is stupid tight.
-tightening things to ridiculous proportions just for fun feels more ridiculous than the 725, more ridiculous than IR composites. I would attribute that to the balance feeling so light, not that it is literally more powerful though.
-this is rather meaningless, but the boot is nicer. It is a textured cover instead of the slick cover from the 725 that nicks easily and writing wears off quickly etc.
While not super light by any means, it reminds me of my older composite IR 2xx5 impacts. Likely because the balance just seems right, which the composite IRs were like that too (I attributed more to light weight but who knows).
Whether it's worth $480... Depends on who you ask. I've been super happy with every $250 IR2135 etc I've bought. They usually last 10+ years before the anvil that snaps for me, which is just stupid reliable, probably better if I actually treated them well. On the flip side, I like to try out new stuff all the time, especially snap on stuff. I support a company I like, a salesman I like, and a local business owner that I like. If it performs as well as or better than whatever I was using before purchase I call it a win regardless. In this instance I have parked my 725, my IR and my IR clone (Matco) for the 850 since release and I am very happy with it. I don't think it's any more powerful than the 725, probably about the same. However the sound and hand feel are a big improvement. When a second gun needs to come out at the same time, the 725 is now choice two.