Could be a KDC-21, which would make it late 80's and which would land it in Whirlpool territory but for the most part it's still a Hobart system.  If it's a KDC-22 it's obviously newer but basically the same machine.  Bottom of the KA line. If you want entirely Hobart, you need to be looking for series 20 or older machines, which have a different panel design and fatter buttons.

OK, that second machine is a KDI-21 or 22, but I don't think it offers the Soak & Scrub cycle.  I thought that was only a Superba thing, and something of a gimmick.  Anyway, it has more features and cycle options than machine #1 but is the same vintage.  I had one of these for 18 years and never had any trouble with it. 

I agree that a KDS-18 would be great to find, but the series 21 and 22 machines are still good performers with similar longevity.  I put crusty un-rinsed items into my ISE Classic Supreme, which is a series 22 clone, and after I've emptied it I check the filter and it's entirely clean.  The filter purges after each wash cycle have consistently taken care of business.

And finally, allow me to narrow your search.  Stop, Stop, STOP looking for an older Thermador or Waste King!  I did my best to give a Thermador THD-3600 a chance to win me over, but after a year of coping with ridiculously high decibels and often frustrating results, I replaced it with my ISE and I couldn't be happier.  The next person to subject himself to the Thermador was in love for a brief period, but the machine quickly turned on him by producing uncleaned dishes and leaving film on everything.  It was evicted, and hopefully did not pass GO on its way directly to the krusher.   Trust me, you don't want one of these machines.

Here's a picture of my 1985 Thermador's interior.  You can barely see a sliver of the upper wash arm, which is a smaller version of the lower one.  These machines might perform well under absolutely ideal circumstances with the world's softest water and super phosphated detergent, but otherwise all bets are off.  I know from whence I speak, as does my good buddy Nate, a dishwasher nut if there ever was one.  Note the chewed up gasket where the rollers for the bottom rack scrape against it.  A sloppy design.  The lower rack would also de-rail itself easily if the load wasn't perfectly balanced.  Super annoying.

IMO, it's not a dishwasher, it's a dis-washer.

Oh yes, the Thundering Thermador did heat the water.  And it heated, and it heated, and it heated, for like half an hour or more on the "Sanitize" cycle.  By the time that particular portion of the cycle was over, the fill for the next wash consisted of barely warm water, since the pipes had cooled down and the heater was a considerable distance from the machine.  That defeated the whole purpose of the steam cycle.  Waaaaay too many flaws in that system.  I'm glad you found the KDS-18.  You'll be much, much happier with it.  A Thermador or WK machine would have only offered frustration.

David, you're correct that in the beginning I was thrilled with the Thermador's performance but not so much with its noise level.  The trouble started when phosphate-free detergent was used, and no amount of Lemishine or Glass Magic or vinegar or bleach was able to correct it.

Still, as I threw more challenges at the TT even before the phosphate-free incident, it would fail me.  I had to scrape and rinse dishes much more thoroughly than I do for the ISE. 

Without a doubt, there is no machine that could dry a load better than the TT, but I'd rather have one that's able to wash a load and I'll put up with having to wipe out cup bottoms in exchange.

As time went by, the results the TT produced were disappointing too often.  I gave it a year, putting up with all of its quirks, and then gave up.  When I found the ISE on craigslist, I didn't waste any time in snagging it, and I haven't regretted my decision to give the TT the boot.  Automatic water heating is the way to go.  The water for the next fill is reasonably hot, unlike what would happen when the steam option was selected on the TT.