sp3 vs ipad/MacBook. Well SP3 competes head to head with MacBook pro. Biggest thing would be operating system preference. Trade off would be more portable and tablet pc capable vs traditional laptop.
SP3 vs ipad. Media consumption, I say tie others lean ipad due to 'weight and battery'. I say take SP3 out of equation and ipad vs my cell phone (note 4). Note 4 took over my media consumption light weight device.
SP3 vs ipad, productivity. Yes and yes and yes, theres an app for that with apple. But until theres an app productive enough to be on par with full programs, then leave apps for play (Netflix, angry birds, ect). You want the ipad to win over a sp3 as a tablet, then give me an ipad with full mac operating system and ability to install full programs, and give me a way to left/right click (pen in surface pro case). Then also give me pen input to write notes. And do all this, while keeping the ipad size/weight/battery the same. Then it might win for me. Until then, my cell phone beats out an ipad, and my SP3 beats out everything else. Unless I need a heavy lifter, and in apples case nothing compares), I then pull out my msi workstation laptop with i7 4810mq, 32gb ram, 4tb of ssd storage, quaddro k5100m, 5 usb ports, and 17" screen all in a nice but 9lb package. Give me a mac product more capable than that at $2500 or any price for that matter.
The surface pro and my cell phone is my everyday, take everywhere, do just about everything on package. The times I need major work done, no surface pro/MacBook/ipad will do and I bring my MSI. But everything else the surface pro does. All in a form factor slightly smaller/lighter than MacBook, or slightly larger/heavier than ipad yet can do both and fairly well.
My biggest peave with people comparing the surface pro to mac products. Is that they compare all 3 of the mac products at the same time, to the 1 surface pro. My MacBook pro is more powerful and better typing on my lap, my MacBook air has better battery, my ipad is lighter and better as a tablet. I mean that's great. Compare the best aspects of all 3 of your devices to the 1 device. Then when you leave for the day, pack up your huge backpack full of all these devices. The surface pro I will admit is not better than the best aspects of ALL apples products, but it meets a very fine line of the best mix of all, while throwing in features not on any. It gives all day battery life if you use it as you would 'any' of your mac products. It weighs less than all but the ipad air in which its just slightly heavier. The 12" screen is the best mid ground of being large enough to be productive, and small enough to be 'fun'. Has built in kickstand so when you do use it while laying in bed/on couch just pop open kickstand and done. Has pen input which for some doesn't matter, but for those that do it is great. No its not as accurate and good as a wacaam tablet, but show me a wacaam tablet that's as thin/light/give battery life/has display/powerful hardware/can run a operating system. Give me a MacBook that's also a tablet or has a pen or is as portable as the surface can be. Give me an ipad that's not just a 10" phone and can do something.