I have both, a 2010 T-bird and the 05 speedmaster. I really like them both but they are way different bikes. I got the T-bird as a 2 up bike (not a trade up), and it does great in that role.

The speedmaster is not a good 2 up for any real distance riding (and I tried). The speedmaster is wicked fun solo bike, and I have no intention of getting rid of mine, I love riding it.

but when it comes to the open highway bird

not sure what year t-bird you test rode, but the power description seems off. Heck mine will wheelie in the first 2 gears without even trying. It has plenty on tap. Maybe the newer model years are detuned some?

05 speedmaster - 1100cc, 11:1 racing pistons, Carillo rods, thunderbike cams, ported and polished head, 2mm over intake and exhaust valves, Barnett kevlar clutch, scepter pipes, oversize manifolds, 45mm HSR's, TTP stage 4 firestarter