With and without groove are depends on brake pad design. There are two possible things you might mean by "Groove" to people in the brake industry.

1) A slot that is ground down into the pad usually in the center is used to prevent cracking, reduce tangential stiffness, reduce fade, and clean corrosion off the rotor.

2) A scoring mark going tangentially on the surface of the pad, generally means that at some point in time previously a small piece of iron disloged itself from the rotor and compacted onto the pad surface. It was then dragged across the pad surface until it ejected from between the pad and the rotor. In this case you'll generally also notice a similar wear path on the rotor.

As seller speak, Ferodo Zero need to run in with soft braking style for roughly 100-150km and Bendix MKT 400'C and GCT 350'C no need. Both performance are good enough enough for street use and also depends on driver braking style, transmission and vehicle weight.

Ferodo ZERO are made in thailand and Bendix GCT/MKT made in malaysia.
I try both pad and both serve me very well.