So I just bought a Hegel H390 and

The Hegel range of amp is very capable indeed, certainly an underdog as compared to many amp out there. It sounds clean and distortion-free even at a high volume.  Running an H590 with Magico S3MKii with good results.

Each generation offers another level of resolution, I remember the h190 being a bit more resolving than the 360, but I needed the power and the 390 wasn’t out yet. Can one of you guys tell me if the step up to the h590 is worth it? 

h390 h590 have a super smooth super suave sound compared to h160 h190 h360 gen... bent holter and crew voiced the preamp section differently in these current top models, it is almost a tubey treble quality, no loss of inner detail or blackness but an even more sophisticated sweet sound

Thanks for the reply. I really enjoy how my blades sound with the h360, but I can't help but think there's still more to hear.

@steve59 A Hegel rep gave me a a 90 minute demo with the Hegel 360 and the top end Hegel monos and preamp with KEF Blade. I think it was Blade 1 and not Blade 2. The 360 was rather good but the separates were using the extra power and sounding better. An incredible demo. 

I would like to hear my CODA #8 on the Blades. It sounds great on my Thiel CS3.7's and the Blades are easier to drive. Once of the reasons I got the CDOA #8 was on the chance I move to a house with a better room for the Blades.