I was a regular subscriber to SI until Mar 1999, and have every copy (from Fall 1976) up to that date.
Good points: for many years of its existence it was the only source for consistent, well-informed sceptical coverage of many paranormal and pseudo-scientific topics. It has attracted many excellent writers and contributors (see list by CalMeacham) and I often found it to be a good repository of factual information that you just don’t find anywhere else.
I think you might find that its coverage is broader than you think, and encompasses a lot more than ‘paranormal crap’. The whole point, really, is that it’s not enough to just be dismissive of ‘paranormal’ claims - SI has a good track record for serving up the facts, research and studies that show precisely why such and such a claim carries no weight, and for running solid refutations of current claims. It has impeccable academic credentials and provides comprehensive cites and references for just about everything you find within its pages.
It can also move fast to deal with ‘hot’ stories - its response to the alien autopsy video was memorably rapid and comprehensive.
Bad points: it’s just my humble opinion, but I think its tone can, at times, get a little dry and dusty; sometimes it carries pint articles on subjects that scream for at least a gallon of coverage; and I agree with some other posters that from time to time it fails to be as impartial and fair as it strives to be.
I agree with Space Vampire that a good first step might be to find a selection of back issues (either in a public library or, more probably, in an academic one) and see what you think.
IMHO, ‘Skeptic’ magazine, published by the Skeptic Society (skeptic.com) serves the same objectives more succesfully. I feel it has longer, better articles, is much more impartial and better at providing room for opposing views to be presented, covers a broader range of subjects, and has a more likeable tone. But I guess that comes down to personal taste.