In my MDB8959SBS I've tried Cascade Powder, Cascade Liquid, Finish PowerBall Tabs, Walmart brand pacs, Melaleuca Automatic Liquid, LemiShine Pacs and Cascade Platinum pacs.
I always go back to the Platinum. Don't get me wrong, some of the detergents do certain things better, the Melaleuca is awesome on glassware and crystal, the Finish is good on stoneware, I use the walmart pacs as my prewash soap on the jetclean plus cycle with power scrub, and I like the LemiShine for general stuff but the Platinum pacs make this dishwasher sparkle and everything in it comes out clean.
Now, I am one that doesn't believe in adding rinse-aid in the dispenser, I fill it with water and let it run out. I hate hate hate having to rinse a glass before filling it with water. I hate the foam. But I have no issues, no spots or marks when I use the Cascade Platinum. My Stainless interior looks brand new, no water marks and my stainless cookware looks absolutely gorgeous. I don't use a lot of plastics, mainly stainless containers and cookware, stoneware and a lot of glass. If I don't run a quick wash, steam sanitize option is always selected. I know it sounds like a waste but the glass/stone/stainless items always seem cleaner and the hotter the non plastic items get the faster they dry. Again, I don't have water spotting issues.
When a cycle is done, except for the quick wash (I only use that during prep with no dry cycle), I open the door and check that all the tops/dips of items are emptied (no puddles) and I leave the door partially opened to let the load air dry. I typically do this in the morning after I've ran a cycle and I am on my way to work. When I come home for lunch or supper I unload the dishwasher and I have no spotting issues, no dried on food, just clean dishes.
I wouldn't say I have soft water but I wouldn't say I have extremely hard water either. Cascade platinum pacs are my go-to everyday pac, but thats what works for me. I know the dishwasher came with two sample pacs and some cascade rinse-aid, after the rinse-aid sample ran out, I never purchased more. Working in catering where we run load after load after load of dishes from a days' worth of prep, I began hating rinse-aid.. Depending on who was drying the dishes, if they didn't rinse the cookware etc, we'd have recipes flop because of the chemical components. I guess that dislike came home with me. The better quality the dish (not plastic) and the hotter you get it the faster it will dry.
That is what I love the most about this unit -- it gets hot.
I hope this helps and I wish you many years of enjoyed usage from this machine!
--edit: Something I noticed when I was looking at lemi-shine's website is that their rinse-aid page says to turn off heated dry.. Cascade's says the same thing.. Finish doesn't mention it but.. I'm thinking with the way the pacs etc are made, maybe its ok/normal to not use rinse-aid if I am using heated dry...
Oh, and this dishwasher is ... interesting when you listen to the noises.. When it fills, it starts and stops several times... If you open the door, the pump starts and stop 4 times before it takes off again and the machine can be used without the top rack, just make sure you are paying attention when you unclip all four clips on the top rack. I have a few oversized cutting boards and large beverage dispensers I can finally wash in the dishwasher.