Adding my 2 cents .The S3 may be "comparable" to something like an iPad Air, but I personally find the S3 noticeably slower then the newest iPad. That's my biggest problem with it. If it could at least be on par with an iPad for basic things like web browsing, I'd happily own one. I just couldn't accept it being noticeably slower for such a basic task.
Comparing the Surface 3 to an iPad is not apples to apples - no pun intended.
iPad runs an mobile OS and everything is tuned to that, including Safari. My guess is that if an iPad Air 2 was running full OSX (like the Surface is), it would be much slower, and more than likely slower than the Surface.