I've spent a few hours trying BB1025x alongside BB425x a few months ago (I also have a BB415 at home). They both sound really good and are well made, but certain degree of higher class is noticeable in the 1025. Front of the headstock is lacquered hi-gloss, finish on the back of the neck is somewhat nicer as well, although hard to describe (both are kinda satin), the nut is made of the same material as frets and it actually does sound better on open strings and particularly harmonics, the bridge is better - not only better looking, but also feels harder when playing close to it. Might be made of denser material or maybe those angled saddles give more tension to the strings. I know I must have listened to differences in pickups and I remember hearing some, but nothing huge. The B string was equally good on both, and even slightly better than on my 415 (which isn't bad at all) - that must be due to those laminated necks. Was the 1025 worth twice the price of 425? I think it sure is worth its price, but the 425 is more of a bargain, as it's almost identical and costs just half... I'm planning to upgrade to 1025 and keep the 415 as a backup (it still will get some proper gigging time, I love its painted headstock), as I actually feel that those bridge/nut/pickups changes are actual upgrades making for a more solid, controlled and sounding instruments, and not just marketing gimmicks. Then again, I plan on getting a Hipshot bridge and a brass nut for my 415, it will probably cost me 100 squids (which is more than I paid for the bass itself ) and get a similar result...