Jag - seeing as your "location" is MacDill AFB - I know the FBO you are going to be training at (Peter O. Knight Airport - TPF).
I'm working on my Comm. tickets there right now and I've flown all of the aircraft they have in their rental fleet.
The Tomahawks are a little faster than the 150 (and actually, the instructor you spoke to was wrong. The 150 is $45/hr. and the T-bird is $48/hr.
).
However, after reading an Aviation Safety report (August, 1997), about the Tomahawk and its tendency to spin in, I - personally - try not to fly them.... but, that's just me.
That being said - most of the instructors at TPF have a ton of experience in the Traumahawks and can vouch for their stability. Even with my aversion to the plane, I still have around 50 hours in them myself and haven't come close to making a smoking hole with any of them.
Please feel free to drop me a line on PM (Privat Messege).
And welcome to Peter O.!!! GREAT choice!!!
R2F