Controllers work in the free web version, too - or, they should, so let me know if you're having an issue. Do feel free to refund the web edition if that was the only reason
The Steam version is an evolved version, more polished and with more features, e.g.
- New vehicles
- New location(s)
- New road styles
- Vehicle customisation and tuning
- Traffic
- A music/radio player
- Improved UI and polish
- Improved controller support (ui navigation and such)
- and ongoing updates adding new content/upgrades over time
Mac support will take some time for the Steam version, Apple have some hurdles in the way that just added too much friction to resolve before release. I'm hoping to get Mac support figured out in the autumn