I would probably go with the dyna. But thats just me. Im too big for a sporty otherwise i would have bought one. I love the bigger bikes though, and im sure you will too as soon as you ride the dyna.
See if you can go out on it, then the choice is all up to what you liked the most!
We don't know what kinda deal your getting but 10,000 is'nt much miles. '06 Dyna's have the 6 speed tranny and EFI. In my opinion the Dyna is one of the best handlin', best looking bikes Harley has. ('specially if it's a Streetbob)..I'd say go for it.
I thought that in 2006 EFI was an option, and was not on everybike until 2007.
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If it were me I would get the dyna, as long as the deal didn't cost me any more money, but thats just me.
I would think that I would go with an 09, especially based on price and warranty period. Try a different dealer on a new one and see if any deals can be made on your necessary accessories