Josh's complaints are valid. I've made the same points before and a few in here agreed with me. He didn't say the OS sucked--just that there are real issues almost two years later that still need to be solved.
I think what Josh is trying to say is that Microsoft is farther behind now than they were 6 months ago. Mango is great, but it isn't enough to put Microsoft on-par with the other platforms.
Android no longer feels like a clunky mess to him and windows phone doesn't have the apps or flexibility of that platform.
I will say, though.. I disagree with his point about multitasking..
The only OS that is doing multitasking the way it should be done is Android. Switching apps in iOS is jarring.. switching apps in windows phone is also jarring.. Not enough applications have been updated to support proper suspend and resume, too many apps have poor scrolling performance or just aren't written well.. and against Microsoft's own apps on the phone, the differences are painfully obvious.
I still love windows phone, and I will be leaving my galaxy nexus behind for the lumia 900.. but I am hoping that Microsoft can turn things around with Windows Phone 8.. and give developers more flexibility to write the kinds of apps that people want to have.