I commute by bike whenever practical, so long as it's not rainy or icy. Regular cycling shoes with neoprene covers work, but they're a hassle and look goofy. These are a much better solution. For me, these are for temperatures under 50 F.
My normal shoe size is 44.5. I ordered a 45 and it fits nicely with mid-weight Smartwool socks under Sealskinz. 28 degrees and, though my hands get cold, my feet are fine. The sole flexes; these are not performance boots; nevertheless, the cleat is deeply recessed and walking is quite comfortable.