At present, Capital One Quicksilver. Gets me 1.5% back, though that doesn't really matter as I'm carrying a balance at 26.99%. XD

While I have yet to finish an article on the subject, I've utilized a lot of fiat credit products over the past few years to finance my living expenses and free more of my income to go to buying bitcoin while I saw the price as extremely undervalued.

In my mind, I'm happy to pay the current average of 12% per year across the range of products, as I still maintain bitcoin will likely do far better than 12% per year.

Not financial advice, and definitely not a good strategy for everyone, but I aim for transparency.