I do not like to make comment on other peoples experiences, but, in this case i will voice my opinion.

As you say,

  First:  In my opinion the art of building things from wood is not a race. It is to be enjoyed for what it does for you. It gives you a sense of satisfaction that you have built some thing with your own hands and it calms your mind. As far as the fact it takes longer to mark out an prepare for the final build it is part of the process of the art of building.

  Secondly: You may have though you bought a good piece of quality plywood but if it had voids in it, it may not be as good as you thought. Another point are you sure of the actual thickness of the plywood was a full 3/4" thick. Did you use the correct screws, remember that Oak is a hardwood. Also did you make any trial joints using a piece of your stock wood to be sure your setup was correct and there was a solid joint. After your failure to make a solid joint did you not think that if used a little glue that it might fix that problem.

  Third: The fact that you used genuine Kreg screws and a fancy battery drill to screw them in has no bearing on the fact that some where along the line you have not used the tool in the correct method. Either your screws where wrong or your hole was too deep. Did you ask for any help , from other members of the community , i am quite sure that if you had you could have been given help from thousands of experienced people.

 As you say " GIVEN MY EXPERIENCE WITH POCKET HOLE JOINERY " . I must say to you go back to your conventional joinery and if you should put you K4MS jig up for sale there will be a whole lot of people ready to buy it. If you want to learn how to use it join in the community , look at other members projects i am sure you will learn a great deal as i have.

  Jock Sloan Brisbane Australia

As Jock said your application with ply is actually more aligned to the quality of ply we have available these  days. Trying to obtain AA grade is almost impossible and the classification varies just to complicate matters further.

My K4 has had a fairly rough life since ita purchase so I also would be interested in upgading too.

Mind you the errors I have had with and damage I caused are mostly operator generated, and could be classed as (RTFM) ones

I have had the old version keg jig, I loved it. Every sense I have bought the k5 I have had nothing but problems, it’s very thin cheep plastic compared to the older version, and I have problems every time I start drilling holes, the stupid  lock piece or what ever you call it comes lose no matter how many time I tighten it. I just did it today as well, drilled 6 times and guess what went to drill agin and it went too deep again, lose. Ruined a project..... I have all the keg jig tools and I am seriously disappointed!!!!!! Price goes up and they become junk.... 

Again i feel compelled to comment on other peoples experiences. You said you had an older version of the jig and you upgraded to a K5 system. The problem you have (if i am reading this correctly) is not with the system it seems to be with the locking collar for the drill.

Did you speak to THE Kreg Rep. about it. As you have had a jig before did you think to try the other drill and collar in your new system sort of a second opinion so to speak.

In my opinion what you should be doing is not criticising the jig, it is that you should be asking what ,if anything , you can do to fix your problem. If the locking collar is faulty in any way i am quite sure Kreg will be happy to replace it free of charge.

   Jock Sloan Brisbane Australia.

Having read #jack Sloane wonderful reply to this issue may I just add - use the force young padwan. 

Careful of your plywood dimensions.  I only use Russian Birch ply for most of my projects as it is a true 3/4" and my screws don't penetrate..  The plywood manufacturers are getting expert at thin slicing veneers so the new plywood tends to be quite a bit thinner.