It really depends on the product you are talking about, I like Microsoft for Desktop OS, Office products and I like Apple for the ipad, ipod and iphone.
Both provide good services and both are not open source. Quality and performance is neck and neck I suppose and there is going to be a tougher fight between them in the future as well.
I will prefer Apple over Microsoft. But Apple is too expensive. Microsoft provides us quite good features at a low cost.