In reply to mark k..

To be fair here it is totally opt-in. I haven't used Freemius yet but the screenshots i've seen show it to be incredibly transparent and fully above the boards.

We already have something like this in our plugin. We ask people to share usage statistics with us so we know what other plugins they run alongside our own, what version of PHP they run, and what their WP version is. It's totally opt in. Some users do it and it guides our roadmap. Others don't and it's fine. It's great to have the data when we can get it.

Accusing a fully transparent opt-in analytics tool of spying is kind of like asking for a ride in my car and then accusing me of abduction. Spying is secretive. Opting into sharing data is not.