Well, really most of what others had said in the thread, I only had to own and use the surface Pro for a couple of days to realize it was true. It was way too heavy and thick, on paper you could say it's not really that much heavier and thicker than say an ipad, but that difference really really is evident when you have it in your hands. It's not a tablet you can use one handed for more than a few seconds, and even holding it up with 2 hands you quickly tire of it, and I'm no wimp.
Another major con, of course, is the battery life. I've been too spoiled by the ipad and more recently the atom tablets where I never ever have to even think about my power cord unless I'm going somewhere overnight, and even then I would probably be ok not bringing a power cord. Not so with the surface, the power brick is pretty much a required item to carry if you are going to be anywhere for more than 2 or 3 hours, maybe less if you push it. Sure the surface pro has more power, but really you can only harness that power for very short periods of time on battery, or you have to be married to a plug, and the surface Pro power brick ain't that small, it's much bigger than the ipad brick, especially when you factor in the 2 cords. But even then I didn't get the feeling the Pro was really that powerful, it didn't play any of the games I threw at it, and IE10 stuttered a lot, although I have a feeling it was a cache issue as it was smooth at first and over time it got worse.
Another con, the DPI just didn't make sense. Even at 150%, pretty much the max you can scale it up before it starts ruining things, you have to squint and really aim your finger perfectly to make things happen. Hopefully MS addresses this, but it's somewhere the lower resolution of the Atom units really shines, and in many reviews they note not much difference between the atom displays and the Pro display even with the resolution difference.
As for the Atom tablets, I did consider getting a Lenovo again but for a few things, otherwise it was an incredible little tablet. The USB has some hardware issues which Lenovo is aware of, but months later they aren't addressing or telling people about, which is unacceptable to me. Also their 3g model is 4 weeks out, and for Lenovo 4 weeks means 2 months in my experience. It's also $949, which is price gouging at its finest, the Dell 10 with 3g AND a dock was $749.
Keep in mind this is for my use that I am putting up my opinions, I can see the surface Pro shining in some other use scenarios, but they are kind of few and far between.