Luxman 505UX vs. Luxman 550AX Integrated Amps

Has anyone compared both of these integrateds? I own the 505UX and like it a lot but am looking for more solid state slam & punch. I actually borrowed the 550AX Class A amp for 1 month about a year before I purchased the 505UX. The only thing I remember about the 550AX was that it sounded much more powerful than it's power rating suggested due to it's high current.
I realize the Luxman's are very refined and have finesse but my 505UX does rock out so basically what I'd like to know is if the Luxman 550AX is more ballsy than the 505UX.

Awhile back I researched the integrated amp field looking to simplify but not sacrifice, my system. My speakers are Salk Sound SS8's that are rated at 87db and pretty much a flat 4 ohm load.

After listening to intergateds from Luxman, Accuphase, Musical Fidelity, etc. I decided on and purchased the Jeff Rowland Continuum S2. It is the most dynamic amplifier I have ever heard. It has the layers of sound, extension and finesse of a really good tube amplifier (VAC) while possessing the drive and dynamics of top notch SS gear (PASS Labs).

The JRDG Continuum S2 is also available with a DAC (which I've heard is pretty good sounding) or a phonostage which mine has and it is pretty damn good, though my Herron VTPH-2 smokes it!

Good luck in your search.

You can't go wrong with Luxman. On paper, the 550AX is the better amp. But it's really up to you to decide whether it sounds better. Is there any chance you can audition the 550?
I did audition the 550AX about a year before purchasing the 505UX. As stated in my opening post, I only lived with it for about a month or less and the only thing I remember was how much power it had for 20W. I wish I could have spent more time with it. I've owned the 505UX for a year and have put it thru the paces so I know it's tendencies.

Thank you for mentioning the Jeff Rowland. I've never heard one but will look into it.
Second recommendation for the Rega. I own their Isis CDP and it their top of the line stuff will compete with anything out there.

Ok, cool, and sorry about that.