I've been using WS281Bs (60 LED/M) for over a year and half now and I haven't had any issues at all really. Brightness and gamma seem perfect to me, I guess they can easily be adjusted via Hyperion too. I think I only paid around £16 for 5M for them too. Also I don't use arduino or level shifter either.
Thanks, much appreciated. Thought I'd do the level shifter regardless of which i went for as it can't do any harm and they're only 49p from Maplin