The Rainbo tights are absolutely fabulous. I only have one pair but they're my favourite pair - so comfortable (especially at the waistband), so stretchy, so smooth. Too orangey for competition wear (I have some Mondors for that), but so nice to wear! And yep, a delicates bag in the washing machine and you're right as rain.
I agree the Danskins were great, I have two pairs of Danskins that I bought in February last year, they are still wearable though one has a run and the other has completely lost its elastic.
My only current gripe is that Rainbo seem to have changed their shipping options so now you can't get any less than Priority International if you live overseas. Which, for two pairs of tights, was $38. Absolutely ridiculous. I paid anyway because I love the tights and need more, but I made sure to tack an irritated note onto the order. The first time I ordered a pair of tights from Rainbo (only last year!), I chose regular mail and paid only $17 for two pairs.