Hello,
If you are going for prostheses in anterior/front region then zirconia will give good results as it is highly aesthetic.
If you need prosthesis in posterior region or in back region then you must go for PFM crown (porcelein fused metal), it has more strength.
Nowadays, DMLS technology is used in making these PFM crowns which give good results.
Next Steps
Don't bother about warranty.
They usually are long lasting.
Health Tips
Don't dealy for crown/bridge as it delaying it may cause changes in occlusion.