Audio research reference 150 vs Pass Labs X350.5

Would appreciate if anyone has compared the 2 amplifiers. I am currently using a pair of martin logan summit.

Was originally on a pass Xp20 Pass 350.5 combo driving my martin logan summits. Changed my preamp to the ARC Reference 5SE and am now contemplating if i should change out my amp from the pass to the ARC ref 150. Wondering if this is a sideways or upgrade and would appreciate opinions.