It depends on how you define "functionality" I guess. I would argue that the 350 dollar i3 laptop I got at best buy for my wife can do anything an ultrabook can do except for battery life. In fact, she plays some online city building flash game with a lot of players online, so it is fairly cpu intensive. So I would argue that for this use, it is actually faster and will run cooler than an ultrabook. She is acutally happy with everything about it except Windows 8.
I will try to refrain from getting into a rant about that, but even though tech savvy people on these forums are starting to accept or even prefer it, it is still very intimidating and unintuitive for the average user.
Yes, its cheaply built, not as portable, etc., but it can do whatever an ultrabook can do. Granted with not as much refinement, but it can do it. That is actually the problem I see with ultrabooks. Unless you want it for business use, where portability and nice appearance are important, you are paying a huge price premium for the same basic functionality.