Comparison: Which urine substitute is the safest and most reliable?

I know this has been discussed in the past but I know sometimes things can change pretty quickly with this type of stuff.

Which specific "brands" of urine subtitutes have you guys found to be the most reliable and easy to use?

I've heard good things about Quick Fix 4.0 and Number 1. It depends on your situation. I myself used Number 1 with excellent results, but by and far the most popular is Quick Fix. Research and see what is best for you.