I have a GoPro 4 Silver. Only used it so far for a weekend at BPW.
The screen can be turned off, so battery wont be an issue if you don’t need to use it, but it is very handy to switch on to check your shot framing or to watch that bit of footage that you just filmed.
The spec is great, I am only going to put my videos on YouTube, not on any kind of imax screen so I didn’t need the massive spec of the Black (and honestly I think that vast majority of people won’t ever either).
End of the day, look at what you can afford, but also remember what you are actually going to use the footage for. Finally, do you have the space, I used around 35gb from my weekend at BPW, that was at 1080 and standard frame rate. Increase that and you will be filling up your hard drive pretty quickly.