I have N950 and also received the free developer gift Lumia 800.

As Lumia 800 and N9 has the same screen, I can definitely say N950's screen is more accurate. It's obvious with small text, for example when browsing. The text is just much more readable in small size.

However, N9's screen has a big plus too, the always on screen with the notifications and clock.

I don't personally car much about the hwkb. I only use it when I'm using terminal. Even then it's just a bit better than vkb, I much more prefer to ssh into the device anyway.

So N950 or N9, it really is a preference. I agree N9 is overall better, but it really depends how much you value hwkb and the more accurate display.

Personally I'd rather take N9 as a "user" phone, but I prefer N950 as a phone to use for developing. The biggest reason is the ease of reflashing the phone with the One Click Flashers, the hwkb is a minor plus.