Although my favorite Mahler is whatever I happen to be listening to at the moment, if pressed I would have to say M6. At one time I had more than 35 recordings, though I've let a number of them go to other listeners. Some I like a lot, but in a way I despair of ever hearing a performance that's completely satisfactory. I would like to hear Stenz.
I have the earlier issue of the Kubelik set. I wouldn't part with it, but it's a space waster with three triple-width jewel boxes in a slipcase. I like the idea of the current issue, a thinner cardboard box, probably with cardboard sleeves. I don't know if it's remastered, but my set is quite listenable, though the sound is a bit dated.