Honesty demands that I point out that I've not used a treadmill motor myself, so my input is much less useful than those that have....
My thoughts, for what they are worth:
The thing that really bothers me is the open frame construction. This, combined with permanent magnets, would seem to make it totally inappropriate for anywhere that ferrous metal dust might be present (even if the machine it will be running does not itself make ferrous dust).
The "dual fans required" suggests it will need a fixed-speed fan in addition to the shaft-mounted one (if fitted; I assume it's part of the drive/flywheel that I'm guessing is just off the right-hand-side of your photo?), in order to provide cooling at low speed. It's not rocket science, but it should be considered.
Other thoughts:
2 1/2 Hp at 130V is 1865W at 130V, assuming 100% efficiency (1 HP = 746W from memory).
Rating is 17.2 Amps at 130V, giving 2236W input.
1865W / 2236W = 83% efficiency
It's high efficiency, and the permanent magnet description, suggests it will need a purpose designed controller. This shouldn't be a problem, but a quick-and-dirty lash-up with a rheostat isn't likely to work well, if at all. On the upside, a quick google suggests the torque curve should be quite nice, with maximum torque at low RPM.
7099 RPM is fast: about twice the speed you'd get from a 2-pole AC motor. Unless you are specifically after high speed, you can probably put a reduction belt drive on to sort this, but it needs a little thought.
If the reduction ratio is large, it is sometimes necessary to have quite a long distance between the motor and driven axes to get enough "wrap" round the motor pulley to transmit the power. It's worth making this distance as long as you reasonably can from the outset, but if modifying existing equipment, you may be stuck with the original centre-centre distance.
This may mean that it may be more hassle than it's worth for things like drill presses, bandsaws, etc. if your main objective is a lower speed range than stock.
On the other hand, if you want a higher speed range than the stock motor gives you, it may be close to ideal.
There are plenty of guys on the 9x20 lathe forum who have successfully used treadmill motors on small lathes. It's probably worth checking out. They have certainly come up with solutions to some of the potential issue.
