Just want to know how accurate the spirit level is on the iPhone 5s ?

I would not trust any phone, but the only way to make 100% sure is to compare it to a real spirit level.

Even having a case on the phone or the buttons protruding could make a difference.

Macworld seem to think it's pretty reliable - http://www.macworld.co.uk/review/mac...eview-3476379/

I agree with the previous poster though, I wouldn't trust it and it seems a bit gimmicky to me.

OP, if this is in relation to setting up a motorised satellite system, I wouldn't risk it! You can get a real spirit level for less than a fiver from B&Q or HomeBase.