I've watched streams of it for the past three years on various others streaming the video. They're not shaky cameras recording with low quality, they're the stream from Blizzard, re-streamed. Sure, the quality might drop from 1080p to 720p, but it's just as good overall. The info is the same and it's free. Sure I miss out on the additional stuff the stream gives, but $40 for a mini pet and a hearthstone card is idiotic. You know what they say though, "A fool and his money are soon parted."
Additionally, MMO and other sites have that information posted within a minute, tops as to what the new everything is. Again, there's no reason to actually buy it unless you like throwing money away.