I bought Cuddledown's pima cotton mattress pad. It is excellent. It went to the laundromat for the first washing but fits in my Miele and washes well. I've used them for years and trust their products and reviews.

This is good to hear, rococogurl. Is yours a kingsized pad. I recently bought a queen sized pad from Costco and on a trial run, couldn't fit the darned thing into the washer. Its refolded and going back to Costco. It was too thick. I bought something from Target and it works. But I will look into the Cuddledown's options for the future. ETA, I too have the regular sized Miele washer/dryer set.

@enduring - yes, king size. It wouldn't fit in washer when new so we took it to laundromat. But once the finishing was washed out it fits and it has improved the feel of the mattress. They are very expensive compared to other sources but I've used them for many years and trust their quality. They have Jan and summer sales so I wait if I need something. Also bought a wonderful summer quilt from them last year. Don't need/buy much so what I do gets scrutiny. Since the summer quilt I no longer need the 4 king blankets which will make their way to ebay eventually -- self-financing LOL.

I bought oura from Ikea, it is on the thinner side but it does the job.

The beds in Sweden have 2 or 3 mattresses, boxspring and mattress or only boxspring and a mattress that is thinner and that we put the sheet on when making the bed.

I have these St. Dormier ones on all the beds. Love them. They have washed and worn well for years. Not bunching that I've noticed.

http://www.snuggledown.com/s/catalog/st_geneve/st_dormeir_wool_mattress_protectors/

Thank you all so much, great recommendations and a lot to think about!

@linus... I had one of those from Ikea, it was very thin and had elastic straps and I loved how easy it was to wash. I liked that it protected the mattress but was thin enough to let you still feel the mattress top. The reason I stopped using it was because it didn't breathe well and actually started to pull on the mattress top and ruin the fabric.

@livebetter... Really like this one. Do you find the color to be OK with white sheets or does it show through?

Here are two more I'm looking at, both completely different though and on the pricey side.

Organic Wool Mattress Pad

(Like how it's super thin/flat and breathable)

Coyuchi Organic Cotton Mattress Pad

(Like how it's all natural/cotton)

Update: Hefel Pure Cotton mattress pad (elastic straps on the corners version!) was the winner. What a difference! Love how it breathes while sleeping and Miele W1/T1 washes and drys it very well.