I once had a 1024x. It surely felt somehow more high end than the 400 series, yes. Everything feels a bit like an upgrade. But although it has the "better" pu's and everything, I liked the 400 series better. The 1024x was heavier and somehow sounded not as "fresh" as my 1000's or the 400 series. So it had to go I think 3 weeks after I bought it. Maybe it is a psychological thing... If a "cheap" bass sounds very good I love that bass, while when an expensive bass sounds good, it is what is expected of it to do. I owned (in my younger years) anything from Wals (3) to Modulus, several Status, Warwicks etc etc... and to be honest, I miss some of them now because I know their today's market price ( oh man..) but not because I miss their sound!
Edit: But I love my 1000MA's because every time I enter a studio it is this bass that get's the job! No matter what other bass was arround. So I am happy.