This is a great topic, and certainly appropriate for the forum. I highly recommend the approach you’re taking to collect an additional return on expenses. I just advise those that follow you to make sure they’re still paying off their card monthly.
I currently use an American Airlines card for my expenses. Downside is its miles are only good for that airline, but the plus is the range of destinations I can get to on them.
We’ve also used the Capital One venture card, which gives 1.5 points per dollar spent.