Sorry, but you believing in something does not make it a fact.
It's true that any non-premium Android device is a lagfest, but it has more pure functionality than the most expensive WP8 phone. That is a fact. And, the experiences on e.g. the HTC One or Moto X are pretty damn polished.
Hang on mate
Google search for
'HTC One Lags' 'Moto X lags'
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I've even seen an S4 personally at a Samsung Galaxy Outlet (Definitely not a cheapo phone) :/, just dropped the notification screen from the top and could see a lag.
Add to the injury that Android OS is not polished, you install an app, and uninstall it after a few days, it may leave some random folders in your phone.
The only thing I like about android is - Its completely open, no holds barred, you can do anything with it. WP8 and Ios are kind of a fortress, you stay inside or get out.
And the only thing that itches me is - The apps are kind of very very creepy, even a simple game of chess wants to see my call log and phone book, huh?
Having said that I stay away from Androids.
I don't say that Android is a bad OS, its good, but it needs to polish itself.