Depends on how you plan to be honest, and what you're being honest about.
A lot of "I'm just being honest" is way to excuse being a jerk. If your honesty can be constructive, then there's not a reason to hold back. If you're just going to be blunt, then you need to tread carefully.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.