CS as a seat / mini cabin is the same whereever it is, just as was the case with the main CW seat - they are all built in the same place, shoved on a chasis frame and plonked into the relevant aircraft. What does differ is some of the non-trivial externalities, so the noise. humidity, air quality are all so, so, so much better on a A350 series (or B787 series for that matter). Hence I would actually prefer legacy CW A350 compared to CS B777. I guess if you aren't a regular flyer then a one-off 777 zonking is easier to tolerate, but the 777 - for all her versatility - is one aircraft whose passing I shall not regret.