I have and will continue to use Miele tabs. I have discovered that 1 tab cut in half with a pair of kitchen shears (due to the water soluble wrapping, breaking them in half isn't a convenient option.) will more than satisfactorily clean the most greasy spaghetti sauce slathered mess I can offer.
The box of 80 tabs cost $32.00. Using 160 half-tabs, that comes out to .20/load, more than affordable.
Peeps on Gardenweb (who don't necessarily know best) tell me that Miele techs have stated that Cascade pacs and Finish tabs simply contain too much detergent per application for the minimal amount of water that a Miele DW uses, and that over time, this can cause damage to the innards of the DW. Don't know if that's true, but it was corroborated by my own DW tech who is supposed to be "Miele certified".
I used to use 1/2 TB of Wal-Mart powder per use, and that did fine, but my blind husband knocked over the little container I stored it in under the sink once too often. I went to tabs and harmony has reigned in that little corner of my OCD world.