Here's some impressions of Jesada's glue joint bit.
The piece is a heavy, impressive lump of metal. In thinner stock, you may need alot of clearance in your table, and a dedicated fence helps because you need to bury the bit pretty deep inside it. Scrap stock helps set the height; centered on the edge, the cutter mills symmetrical grooves alternating face up/face down.
Fence location takes some noodling. You can start with shallow cuts and deepen them; too deep, though, and you'll get snipe at the end of the cut. Splintery woods like red oak might best be done in several passes, but I had no problem going full depth on 4/4 cherry. The resulting cut was smooth -- an excellent surface for gluing.
The joint gives lots of glue surface and indexes the edges, so you can clamp up without having slippery planks sliding all over. A toothbrush will help spread the glue into those little slots; I used Poly glue so I had time to mess with levelling.
My bit was a little tight & the joint would not come completely closed. No sweat -- just raise (or lower) the bit the teeeeeeniest degree & pass all joints over it again. Serious sharpening will change the geometry & the joint would get loose.
The glue joint bit is expensive for a dedicated tool; unless you do alot of panel glue-ups, a slot cutter t&g setup is more versatile. But as part of Jesada's kitchen set, the bit is a very good buy.
By the way, each glue joint eats up 1/8" of total panel width. If you're shaving things close, it helps to remember that. Guess how I know.