I beleive I'm in the minority here but this is what I am going to do. I will pay my 1040ES taxes with the card - yes there is 2.29% charge but I don't care. I will use my 241 for (2) F seats from either IAD or JFK to DEL/MOM or CPT. These tickets are around $12,000 to DEL & $15,000 to CPT. I will have "invested" around $9,000 for my (2) tickets when it's all said and done.
For my wife & I this is a good use of our money, time & miles. YMMV!