It's free, offered as a standalone service separate from Office. You just need to sign up with an email address from a non-free provider.

https://powerbi.microsoft.com

Disclaimer: I work for Microsoft.

It didn't work well in safari unfortunately. I use Tableau often so I'd like to see a competitive offering.

What part didn't work well for you? It's intentionally designed to work with all modern browsers.

Any idea when the mac version is coming, if at all?

I'm not sure about the Desktop app, but the web app should work in any modern browser today. Features are generally prioritized using user feedback, and this is one of the top suggestions on the ideas site:

https://ideas.powerbi.com/forums/265200-power-bi-ideas/sugge...

As part of Office 365 it's in E5 ($35) or as an add-on to other levels for $10 (per user per month). There's also a limited free desktop version.

https://powerbi.microsoft.com/en-us/pricing/

The free version of the service is too limiting to be very interesting to us. However, it is available from Microsoft resellers as a standalone for about $10.00 per month per user with no contract.

The free desktop version is not limited. It's very powerful. The growth rate is astounding. We get significant new features every month, sometimes weekly.

If you compared PowerBI to Tableau 6 months ago (or even 3 months ago) you are out of date. Its data model capability is far superior to Tableau. The formatting and graphics capability is catching up quickly. The intuitive UX is first rate.

(We are NOT Microsoft employees.)