What do you actually look at when choosing a proxy provider?

I'm working on ProxyClarity, a tool for comparing proxy providers based on specific requirements rather than a generic ranking.

One thing I'm trying to handle carefully is missing data. For example, I haven't run my own performance benchmarks yet, so I don't include unverified speed or reliability scores in recommendations.

I'm curious how other people approach this.

When choosing proxies for scraping or automation, what matters most to you: price, location, IP type, sticky sessions, success rate, or something else?

And would you find a comparison useful if it clearly showed what's known and what's still unverified?