Since the Lenovos have been mentioned here a few times, I'll throw my two cents in...
I would stay away from Lenovo...I bought an IdeaTab last year...While it was really nice, and I liked it...(other than Windows 8)...three months later, I was having issues with a very cheaply made and poorly designed microUSB port...After sending it in, it took 3weeks to get it back, and it STILL had the loose USB plug!!...They sent me a new USB charger cable, saying THAT was the issue...Although, I had told them i couldnt factory reset my Windows install, due to partitioning the SSD, and I wanted them to re-image it to factory spec...To do that, I guess they had to replace the mainboard... ???
Ever since, it has been glitchy as far as powering up and down...Sometimes it would refuse to power up...
So here it is 6mos later, the USB plug is as loose as ever, and now it just died while I was using it and wont power up at all...So another lengthy call to customer service, which is horrible, to get it sent in under warranty for a SECOND time...
You get someone in the Phillipines, who is very difficult to understand, and they run you through about 20 mins of repeated "Well, are you SURE the battery is charged?...", "Are you sure you have tried it with the charger attached?...", "Lets do a factory reset..." (on a unit that does not power up at ALL)... Yeah, OK....When I get it back again, it is promptly going on eBay..
I suggest WHATEVER brand/model you lean toward, look for online forums dealing specifically with that model, and see what real-world issues people are having...I've learned this the hard way.
And actually, Windows 8 is NOT all that different from 7...Especially since the 8.1 update...though there ARE a couple major issues with 8/8.1 that I really hate Microsoft for, and hope they wise-up and fix in a future update, or at least put back into Windows 9 when it comes out...