All the cap serves the same function; You have to choose based on financial condition what u can afford. Still the best caps in market are the zirconia caps. And placing a cap after rct is mandatory.

The function of the cap whether it's metal,metal ceramic or pure ceramic is the same that is to get back ur chewing efficiency and to protect the root canal treated tooth from further damage as it is brittle after root canal treatment.if look or esthetics is not a issue u can opt for metal caps,if looks matters to u and u cnt afford to go for pure ceramic caps u can go for metal ceramic,where it will be having metal insde and outside tooth colour,if u are financially fine u can opt for pure ceramic (zirconia caps)any of the above  caps comes with a warranty from the lab which can be between 10-12 yrs.there are international labs which makes caps and local labs also,at the end of the day choice is urs..

Hi..always go for Zirconia crowns. They are best Regards

You should opt for all ceramic or metal-free crowns like zirconia,lava as they are very strong regarding the chewing capacity of a molar tooth.

Go for zirconia cap they are comfortable ,light weight ,gud in strength ...as well as in esthetics

Better go for zirconia cap