Well... PH's are not as strong as M&T, I agree they are ugly and they are not a good replacement for all M&T but my experience says they are not as bad as some portray.
Look at
formatting link
uses pocket screw joints for all the upper aprons, pockets under the shelf and one screw up at an angle from under the lower spreaders arch up into each leg. Combined with dowles in the pickets and the top attached with table buttons this unit forms one hell of a strong frame.
I have proof of this, one that I shipped was destroyed by a FedEx Ground contractor. It was eventually returned with fork lift tire marks on the box. The top was broken from the unit, two pickets were completly dislodged and the frame was still solid and stands on all four legs as flat as when I shipped it. I intend to repair it someday.
Would M&T be stronger? Yes. In fact I plan on building a set of this line for my home and I'll be using M&T, but pocket screws can save time and provide a strong joint.
I also use them occasionally on solid wood case work, table legs-to-aprons (with added transvers braces), etc. and have not had any problems. On occasion I'll add longer screws if using a soft wood or landing in an over-running panel dado.