While I don't think the screen is bad or anything, I would suggest that you wait until you can test it in a store.

Compared to my LG TV, S-IPS and S-PVA display (connected to my PC) color accuracy is indeed quite poor.
E.g.: On the phone's screen I can barely see a difference between red and (red) orange-red while the difference is very obvious on my other screens.
But brightness isn't an issue imo. I'm able to read everything in bright daylight (haven't had a chance to test it in summer sun obviously ^^ edit: but so far it's better than with every phone before).
I had a Samsung Galaxy Nexus before. Compared to that the screen's resolution is an issue for me because I can't read very very small texts on websites without zooming in. Or maybe the software isn't yet ready to accurately display small text? idk.

But for the moment I wouldn't go back to any other OS. The gestures are so much faster and more intuitive than home and back buttons etc. Phones with buttons, especially physical ones like the Note 3 / Iphones, suddenly feel awkward and outdated.
For a phone the headphone sound quality is good too, which is my main use of mobile phones.
So while I am certainly not amazed hardware-wise, the software is imo already miles ahead of iOS and Android (never had a Windows Phone, but it is slightly better than Windows 8.1 on a tablet, but only by a bit. I still like Win 8.1 - it's not as far off as the other two)