Would This Amp Be Worth The Cost?

So I guess it’s time to sell all of our amps and buy Chinese $400.00 amps. They don’t make a difference? Nor does anything else. Lamp cord for speakers, interconnects, power. My world just got a whole lot cheaper...

To the OP, Musical Fidelity makes some good products for the $$, best thing to do is audition... really, it’s the only thing to do. Then choose which you prefer. 

Geez, my wife (and she isn’t “into it”) can hear the differences between amps... trust me, I’ve had a few now. 
To the OP, I agree with what you were told by the sales guy. Current can make a significant difference, possibly very profound. A class D amp is going to sound very different from a class A amp, even A/B, different circuits. Just is what it is. Then you get into SET, FET, MOSFET, bipolar circuits within all of that. They all have sonic signatures. I also agree that a tube preamp into an SS amp can make huge differences. “Better” is in the ears of the beholder... I just put a Rogue Audio RP5 into my system with a Pass Labs XA25, so far the combo is great. The Rogue replace an XP12 SS pre. The tubes just sound a bit smoother, more “natural” to my ears. No listening fatigue at all. Anyway, this game is about experimenting and finding the best combo you can afford... it’s a lot of fun. Sometimes.