My comments match a lot of everyone elses', but between Apple's WWDC, Microsoft's surface and Google I/O, I was personally most impressed by Microsoft. Yes, the demo had that embarrassing lock-up but the products were a surprise (to me) and I was pretty impressed.
I thought Apple's was the most boring - lots of updates and minor tweaks but nothing really exciting. The Siri improvements are nice, but for the rest... I turned it off before it ended. For Google, I thought the skydiving glasses were essentially a sunglass-sized video recorder, I don't see the excitement. Yes, I have seen the Glasses demo video and I can see where they are heading and it's neat in a sci-fi sort of way, but it doesn't seem really useful to me. And then Jelly Bean has some nice tweaks ("butter" and especially "google now") but I can't picture buying a Nexus Q for $300 (~$100, maybe $150, but not $300), and even the Nexus 7 seemed like a Google version of the Kindle Fire which is a product that I had no interest in. Meanwhile I was pretty impressed with the Microsoft Surface - demo glitches and lack of pricing/availability aside. They mostly sold me on the whole Microsoft tablet concept and I'm really interested to see what they will be doing... which is a huge shift in my mental mindset where I had Microsoft written off as something like a lumbering dinosaur that was going to die within a half dozen years.
So of the three, I thought Microsoft won the "buzz award". But "buzz" doesn't make money and it will be really interesting to see the autumn line up of devices. In particular, I want to see the next gen Nexus phones. I've decided that I will never buy another Android phone that's not a Nexus.