Quickscrews has good pocket hole screws but most importantly they have good (to me equivalent) screws for the HD jig. They are the same specs #14, 2-1/2" with a pan style head just like the Kregs, but they have different thread pattern. I have tried them side by side and in my super scientific testing it didn't take more effort to destroy one joint vs another. I have several sizes of GRK cabinet screws but haven't found a situation where they fit properly in a pocket hole.
I have the K4, Jr, HD, the shelf pin jig, and maybe some misc pieces of the deck jig setup. The K4 is very convenient but the K5 has features that make it worthwhile if you are using it a lot. I like to use the HD jig the most, generally I glue and use a corner clamp but a lot of what I use the HD screws are ply into 2x material so the corner clamps aren't always perfect.
Pocket holes aren't necessarily as strong as a mortise & tenon, but unless you want to put way more money into a Domino, which still isn't a true m/t joint, you aren't going to get anywhere near as quick & convenient making tenons.
I have the K4, Jr, HD, the shelf pin jig, and maybe some misc pieces of the deck jig setup. The K4 is very convenient but the K5 has features that make it worthwhile if you are using it a lot. I like to use the HD jig the most, generally I glue and use a corner clamp but a lot of what I use the HD screws are ply into 2x material so the corner clamps aren't always perfect.
Pocket holes aren't necessarily as strong as a mortise & tenon, but unless you want to put way more money into a Domino, which still isn't a true m/t joint, you aren't going to get anywhere near as quick & convenient making tenons.