My 217 works well with the 752s, sounds excellent in fact. The 217 was a budget amp in its day and the 752s were £500. The speakers work better with the 717.
Likewise, for the CDP - there's more of everything. I'm not knocking the 355, but there's limits to how many things it can be compared favourably to and likewise how many things it will work well with.
While it may sound "good", that's not to say that it will outpace the K2, a 375, an Exposure 3010, something from the lower end of the Pathos range, Eastern Electric's Minimax and so on and so forth.
Like I said, my Sansui 217 sounds good and can punch above its weight, but it matters not my not having heard it - by the time you've compared one amp, or source, or speakers against any other number of bits of equipment, any opinion or review is almost irrelevant against what your own ears tell you.
Yes it can compare well, but - and it might be that you need to have a significant outlay to improve on it - that doesn't mean "outperforms". It just means that £250 from Richer Sounds gets you good performance, terrific VFM and not necessarily an amp that betters one at £1k.
All really depends on what the prospective buyer wants, but I'd be comparing it for price alone - £750 saving for 80% of the performance opens the door to a NAD power amp or bridged option which would be a worthwhile consideration as well.