I have an x220t convertible tablet and it's a nice device but it simply isn't the same as using a pure tablet, as you said, too big and bulky. My favorite form factor is the folding clamshell hybrid. You pretty much get all of the benefits of both an ultrabook/laptop and a tablet.
The battery life and weight of Clover Trail devices are what makes them interesting. Engadget gave the Tablet 2 a pretty nice review, I don't like the keyboard implementation though, wish it were like the Helix. I really love my Samsung 500T, just a great device for note taking with OneNote, fast enough for that purpose and lots of battery. You're not going to be doing a lot of desktop gaming or Photoshop with the Tablet 2 however,
Well that is the point. I tried to use the Pro as an ultrabook and it does not work. Almost everything I need the ultrabook computing power for, all those cores and Mhz and Ram that I give precious run time for, all those things that make this thing need a fan, whine, warm up , be too thick and heavy to handle with one hand for more than 2-3 minutes, all those things that makes the Microsoft Surface Pro $1100+tax with the keyboard are programs I definitely want a mouse + keyboard + a screen around 15 inches. I tried to play games and the screen is too small. I tried to do lots of matlab and the screen is too small, i tried to edit circuity in pspice and guess what, the screen is too small.
Most of the time I am sitting in my chair like the hunchback of NotreDam trying to align the pen to the perfect spot in order to minimize one window and not close the other. If it is a comfortable distance away from me then I can't read or see anything ( I have 20/10 vision) , if I scale everything or lover the resolution, now I can't fit anything in the screen.
So overall, I ended up giving up battery life and carrying a hefty weight, thick and expensive machine to do things that can be done with an atom ( hopefully). I am going to write in Word, edit excel spread sheets ( sometimes), take notes in one note 2013, read pdf text books, record lectures with the internal microphone and an external camera( hopefully it has enough ummph to run an external camera, mic and one note at the same time) and watch a youtube video here and there.
Lets talk about Helix
Helix would be awesome, Helix is actually exactly what I need. The screen is one inch bigger than surface but the tablet itself is lighter and thinner. Keyboard is real and adds battery life, clamshell is an actual laptop yes great, but it has been delayed one time already, when it comes out it is going to be sold out instantly before I decide to buy it and i think $1499 is a lot of money. Maybe I'll wait for a sale for the prices to go down on it and then sell my thinkpad tablet and buy the Helix. Maybe i'll just wait till haswell. I am pretty sure I am going to end up with it, the question is when.
Note: Two things that sped up my decision to return the surface pro.
1) The pen does not store in the device and yesterday I had to come back home from school just to grab the pen that I forgot at home, since I wanted to use it for note taking.
2) After exactly one day of note taking, the upper left corner of the back of the device was already showing wore out paint. I could see the metal under the paint on the casing, half a circle about .3 inches in diameter. I had an iphone 4s that I carry in my pocket with some change and my keys for the last 10 months and I can count the amount of scratches on the device. I have dropped a full thermos ( which was inside my backpack, which was full of textbook as it was falling) on the lid of my sony vaio and the stainless steel thermos was bent inward about an inch, there is not even a scratch on the vaio, let alone damage to the screen. After owning devices at that level, paint wearing off after one day of use made me sick to my stomach basically.