I get to mandate the browser the work system supports (which is Chrome because that was what the majority of users used when I started so I went with what would cause the least amount of pain) but every feature I rollout works with Chrome, Firefox and mobile Safari (I test all three).

It adds very little extra work with the advantage of surfacing edge cases/issues that might have bitten me even if it was just Chrome in the mix.

Also from a business risk point of view tying the entire platform to a capricious vendor is dangerous and I've been around long enough to remember the days of IE5 then 6.

Once bitten, twice shy.