Catch up with what? One of the differentiators of Windows Phone was originally supposed to be that Microsoft wasn't allowing reskinning at all, and while the "special relationship" with Nokia was rumored to allow them a little more freedom in this regard, they certainly haven't used it much.

So long as Samsung and HTC Windows Phones offer the same experience as Nokia, they've caught up already. In fact, they'd "caught up" before Nokia even shipped! So, who's playing catch-up here anyway?

I can think of a few things:

- custom apps ( even if it's not on the phones by default) - marketing. once you've got your phones so much associated with and OS, it takes some time to convince your existing users that they'll need to change

..but play catch up to what? It's not like Nokia has outdone themselves by customizing Windows Phone.

They did have significant distinguishing features previously, specifically their Nokia-specific apps like Nokia Drive and Nokia Transit. Drive for one, I speculate, drove a lot of adoption for Nokia within the WP market. It has received several favorable mentions even on HN, and personally I find it better than either Google's or Bing's navigation apps.

However, that strategy seems to have changed, with Drive being licensed to all Windows Phone devices, regardless of manufacturer. So they do lose a major differentiating feature, but they gain something else: the ability to make money on any WP device sold. I guess they prefer to differentiate on hardware going forward.