The Dimension you can also get panel ready. Depends on if you want it to use a wood cabinet panel or like the stainless.
I have the Diamante Plus in stainless which is the model right below the Optima and was $450 less. I think it was $1400-ish when I got it 2 years ago. But a new Dimension at $1550 is a good buy, I'd go with it over the Optima, as there have been posts in here about issues with it. Though I haven't had issues with my Diamante Plus.

hi fauguy, thanks for the feedback. i just searched on the old optima threads and it does indeed sound problematic. i guess i will have to have to figure out if i want to do the stainless steel look or hold out for a panel ready newer model.

When our kitchen was redone in 2006, I didn't know about Miele, so we went with a GE Profile dishwasher, range and OTR microwave. The range and microwave worked fine, but continued to have issues with the dishwasher. Got it exchanged under the Lowes warranty for an Electrolux. It wasn't any good and was repaired 5 times in 3 months, so Lowes refunded us back. Was then without a unit for 2 year until we got the Miele in 2010. We went with the stainless front, since we decided as appliances needed to be replaced, we go with stainless so they would all match. BUT if I were redoing my kitchen now - I'd get the panel ready Miele so it would have the wood cabinet facing on it.

The basic model had really all the features I NEEDED. The Diamond had several features I wanted. I wasn't willing to pay all that extra for a few more things I wanted and a bunch of stuff I would never use. Decide what's important to you in features, and cost. If they had a Diamond for a couple hundred more than the base model, I would have went for it. Since that was not an option, I went for the machine that serves it's purpose, which is washing my dishes, and it does a fantastic job, the base model!! I can use the saved cash on another part of my upgrade.