I've always had my club call a mini-cab for me & the price is determined up front. As Jenbel says, if you're doing the mini-cab don't get it off the street & make sure you know the price before you get in so as to avoid unexpected price hikes.

I've also walked back late at night to my hotel at times, and didn't feel unsafe. As others have said, take the usual precautions (aware of surroundings, etc, etc).

Cheers.