I think the metro UI is genuinely interesting and (dare I say it) exciting. The logo redesign fits with our times - but it's incredibly safe .. verging on dull.
Large corporations have so much ubiquity .. we encounter them so many times throughout our day. Daily exposure ensures familiarity and this familiarity eventually leads to acceptance; in one sense the logo could be virtually anything and would still serve its purpose (e.g. Pepsi redesign).
The age of the logo is over in my opinion .. these days the prominance of a logo has been supplanted by a fuzzier, more Machiavellian concept - the ability for a brand to connect with its audience on a personal level. In that respect a logo is sometimes simply fodder to for the latter; ensuring the brand and company are spoken about socially (e.g. the gap redesign / 2012 olympics).
It pains me to imagine how much Pentagram were paid for this.