Not worth it...
...I got the postcard in the mail about paying taxes with AMEX and the fine print says there's a 2.49% fee from the 'service provider'
I owe roughly $6,000 in taxes this year and just don't see the value in paying $150 to get 6,000 Starwood points. That's almost a Cat 3 room and I can probably get it for $150 anyway.