Last year, I flew CX777 in lie flat in J seats. Despite preferring CX753's departure time, I chose CX777 as the earlier CX753 flight was using the old J equipment.

For early next year, I'm deciding between CX753 and CX777 in J.
Based on dummy bookings, both flights are now using the lie flat equipment.
On Flightaware, I see that CX777 was subbed with B773 on 11 July - is this the plane with inferior business seats?
On the other hand, CX753 never got subbed during the past fortnight.

Earlier this month, I flew CX753 in Y - the catering was a small, cold chicken sandwich and a cupcake, which makes me wonder - does the 00:20 flight get the short end of the stick in terms of catering in J as well?

Between CX753 and CX777, which flight is less likely to give me a nasty surprise?