I have a 335, a CAT Ultimate and WP 5.1's. I'm very happy with them. I can tell you the 335 is a step above the 333 which I compared head to head. If you believe the advertising the newer dual mono single chassis amp's have improvements from what they learned in developing the Reference 33.
While I've never heard the 33H I'm sure it's better than the 336. At your level of equipment are you sure the $6000 difference(used)is material? If you got the 336 and saved the money, won't you still be second guessing yourself even if you like the 336, which you most certainly will! If you had the 380S you'd have a harder decision but given your assault on state of the art why stop short now?
While I've never heard the 33H I'm sure it's better than the 336. At your level of equipment are you sure the $6000 difference(used)is material? If you got the 336 and saved the money, won't you still be second guessing yourself even if you like the 336, which you most certainly will! If you had the 380S you'd have a harder decision but given your assault on state of the art why stop short now?