Don't find the original QB's stock to be uncomfortable and the length isn't bad for a normal sized person. Rubber butt pad would have been nice, and i might have bought the 78D model if it were avaialable at the time just for that. Not that they recoil, but a rubber butt pad does let you stand it up with less chance of slipping and it's darned hard to crack a rubber butt pad.
The delux version and the 79 both use the thicker diameter barrel from the AR2078's...it's only about 1mm larger in diameter, which isn't a whole bunch, but does make for a little more weight forward where it does the balance the most good.
Both the 78 and the 79 have the same basic butt stock...only the length of the fore arm is different. It's a small stock, but it does fit surprizingly well. Certainly isn't a perfect stock, but it does work well with iron OR with a scope. the delux version seems to keep that well thought out shape.
The target version DOES have too short a stock...that one does need to be longer, and Mr. Archer has a version that cures that problem (as well as selling an extender to retro fit older guns). The one pictured below has an inexpensive adjustable butt pad fitted... needed the length.

Now I've got to justrify antoher QB....may not go with the 79 as bulk fill doesn't thrill me right now...but I'd have to figure in the $ to rebarrel one to either .20 or .25 to justrify it a place in the safe.
But i like the stock feel and fit well enough that I'd proably keep the issue wood (may refinish it after i bugger it up hunting for a year or two, but that's about it).