12310/09 is not IRCTC I guess, so comparing is not possible. And Base kitchen is always a base kitchen, no matter where it is situated. Dal/Sabzi etc is made once for all 3A passenger whether it be Rajdhani or some other train like Duronto so, quality will not differ much as it used to be earlier, but quantity and extra items in the menu is the thing which makes Rajdhani/Durontos stand aside.
.
I suppose that you must have seen the episode of Natgeo "India's mega kitchen: IRCTC" if you did, then you...
more...

must know that they made all in one go without discriminating. And then they said: "Aaj ka consignment hai Howrah Rajdhani, Mumbai Rajdhani aur Sealdah Duronto"
.
So Rajdhani ka khana jo banta tha pehle onboard wo 10x Acha tha jo ab milta hai. And this is IRCTC, their quality differs time to time.
.
Do you think that Base kitchen has time that: Oho! Ye 12260 ka khana hai, ise sabse acha banao, MDH ke masale dalo.. and Oho! Ye 12302/12952 ka khana hai, in dono ko alag alag banao uar ADI RAJ ka bhi alag banao. They really don't have such time on hand to make food for every Raj separately. Thus, people saying 12260 ka khana is best is not that true, jis din 12260 ke 3A me acha khana gya hoga us din 12952 12302 ko bhi gya hoga.. and so.
.
However, there are much bigger vendors like MOW, and they make Rajdhani Class Food separately from other SFs in which they serve. MOW has large no. of diverse category trains operating with their food but here IRCTC has some 4 or 5 trains that too Rajdhani/Duronto Class.