here comes the onslaught
I thought a comment on slashdot recently specifically on the topic of the dual UIs was excellent.
they cited this microsoft paper
"The Windows® 95 User Interface: A Case Study in Usability Engineering"
"Separate UI for Beginners
The first major design direction we investigated was a separate UI ("shell") for beginning users. The design was quickly mocked up in Visual Basic and tested in the usability lab. (See Figure 4.) While the design tested well, because it successfully constrained user actions to a very small set, we quickly began to see the limitations as more users were tested:
If just one function a user needed was not supported in the beginner shell, s/he would have to abandon it (at least temporarily).
Assuming that most users would gain experience and want to leave the beginner shell eventually, the learning they had done would not necessarily transfer well to the standard shell.
The beginner shell was not at all like the programs users would run (word processors, spreadsheets, etc.). As a result, users had to learn two ways of interacting with the computer, which was confusing. "
"For these reasons and others, we abandoned the idea. Importantly, because we used a prototyping tool and tested immediately in the usability lab, we still had plenty of time to investigate other directions. "
Those same conclusions should of been drawn with the new Metro/Modern/whatever UI. MS was too impatient, they should of taken the time to do it right, don't give two different UIs that you have to switch between. Especially if they are not compatible with each other (e.g. doing certain things can only be accomplished in one or the other, and I have read things like IE is separate in each, not having any knowledge of the other as well).
For that reason alone Windows 8 should of never had been allowed out of the gate. Forcing the same metro UI on windows server 2012 (which they do if I recall right - one of my friends who is a MS employee was complaining about it recently) is even more absurd.
Also it appears that the low end Win8 laptops are getting terrible reviews and high return rates (too slow, bad quality, etc). I imagine the cost of the touch technology just compromises the rest of the system too much for a low end box.