What 50wpc or higher amps have a totally different sound from Pass Labs, in a good way?

A pair of Atma-sphere M60s would be a different, high quality, approach. Tube, OTL, balanced. 

Opposite? Not sure what that means since Pass occupies the space between solid state and tube sound IMHO. 
Different- audition a CJ Art 150. Beautifully captures rhythm, pacing and inner detail. Great Imaging and very musical without the drawbacks of some older tube gear.  

Would love to hear CJ Art line, Ayre, Atmasphere. Clearly high end, unique designs. 

I’m not sure totally different applies, especially when come to Nelson Pass amps. With the First Watt series included; Nelson Pass has become the Baskin Robbin’s 31 of amplifier designers.  If restricted to Pass Labs gear, and again I’m not sure totally different applies, but in the context of the gist of the question at hand, Spectral jumps to mind as leaning towards the opposite direction.

Would love to hear CJ Art line, Ayre, Atmasphere. Clearly high end, unique designs.

@redwoodaudio These would be in my top 5 to try also. Atmasphere, Ayre, Pass, Luxman and CJ...all great choices and established, well-liked companies with well-built gear. I don't know about Luxman support but the other 4 are great.