Funny. Similar camera, totally different results.
My *ist DS stays in manual mode most of the time. Split-screen add-on, just like you. I get a great deal of joy from my M42 and T-mount and K-mount lenses, and I use AF and AE sparingly. I find it utter simplicity to turn off the AF switch on the body, flip the knob to "M" for manual, and set my aperture and shutter speed (and ISO) myself.
The camera does just what I expect it to do, and is very easy for me to control - as much as a manual film camera. In fact, I often carry a Pentax-based film body to interchange lenses.
It adds certain abilities film cameras do not have, such as the ability to set ISO on the fly and the focus indicator light, which is close to perfectly accurate (I sometimes disagree with its assessment, but I can ignore it). I can also set a custom white balance, which saves time trying to correct color casts later.
In short, I love it. Auto-everything when I feel it is appropriate, full manual control whenever I want it.
My only consideration now is whether to replace my aging *ist DS with a K200D or a K2000 (don't really want the K20D).
What split screen are you using Bill? I can't get my diopter to a correct setting, for some reason mine seems to get changed (I am thinking the wife is doing it to drive me crazy).
I can't get my M42 lenses to mount correctly either. I need a partner camera geek to hang out with. I am sure it is just a simple thing that once I see it done correctly once I would be all set.
I switch back and forth from auto to manual mode too much. I pick up the camera expecting one thing and always get some thing else. My ME Super isn't that disagreeable.
All this said, none of it is user error. My problems are all the camera's fault!!!😀