Well, looks like that's a settled question! My vote went to pocket screws, assuming you mean methods for joining stiles to rails. I would find it even more interesting to find out what everyone's preferred method is for attaching face frames to carcasses. Since I stopped shooting pneumatic nails thru the face frame into the carcass I seem to use a different method every time (glue only, biscuits, tongue and groove, pounding the FF onto clipped nails in the carcass, even wood pegs), and haven't really liked any of them. But I like frameless cabinets even less, so I gotta settle on a method.
Mortise and tenon is the best option by far in my opinion and the only I use when building furniture but to time consuming for building kitchen cabinetry , I prefer biscuits over screws because when machining the face frame such as dadoing the back a screw can cause a Boo-Boo .
In woodworking " one method fit all " does not apply,
It's a fallacy that face frame cabinets are any stronger than frameless! And if you're using the frame to "square up" your cabinets, you're doing something wrong!