2. Gruber links to him a lot, and he writes well. More cynically, he has modeled his writing style after Gruber's, so if you want more of a Daring fireball fix, you read Marco.
I don't think Marco's opinions really hold anywhere near the weight of John's. Some just have an appreciation for this style of writing.
because he always has something to say. You want a quote from somebody recognizable on an apple-related news story? marco will already have one for you.