The K1000 is a great no frills camera, a truck, a diesel, a marathon runner.
And they are in plentiful supply, as these were bought by the ton for teaching/learning.
The only drawback is that being the KNOWN basic Pentax model, the prices may be higher than for, say, the KX or even MX... I have a KX and yes, it's built very well indeed. I also have a Program Plus, and it too is a solid camera, though with an entirely different feel. I think I prefer the Pgm Plus for everyday use.
What the "better" cameras add are usually "features" which tend to be either photographically insignificant or applicable only on special circumstances. But the market place and the typical male photographer
wants these bells & whistles...
The other direction, the "Consumer" cameras of the 80/90's, was to make a SLR s much like a Point &Shoot as possible. These are cameras with program or Av
only - ie. no manual settings possible. Not bad cameras, but this would represent a photographically significant "feature"
[and why the ME Super is preferable to the ME]
If you want to attempt to stay rational about the camera choice, and there's a special requirement you have, then by all means narrow down to the bodies that have a feature to satisfy the requirement. Otherwise,
it really doesn't matter which Pentax body... This is how I ended up with most of mine: the Pgm Plus came with a 28mm SMC-A and I won the auction at a low price. The KX was at the local photo store. Had each been a different model, I'd have happily snatched them up.