How do I determine the legitimacy of a bitcoin service?

I'm trying to compile a list of things that people should look/ask for before trusting services which ask for personal information and or bitcoins.

What I have so far:

Reputation - How long have they been around? Have they made a meaningful contributions to the community before? (Posts on forums/reddit, wrote open source code, submitted ideas, etc.)

Publicity - Have they made a public appearance or disclosed their location? - Have they made an appearance on OnlyOneTV? Or anywhere else online? (YouTube channels, podcasts, etc.)

Professionalism - How 'professionally' do they handle themselves? How sincere are they? (Do they go out of their own way to help you?) How professional does their service look? (The more effort and attention they put into the service, the more likely they are to care about it and its users.)

*Side Note* Just because someone does not meet all the criteria does NOT make them illegitimate. Use your own judgement!