It does have a problem picking up fast....you have to get it going and then jump on and that's risky.
Too dangerous for jumping on. But since it takes just as long to slow down at the end of the rep as it did to speed up to begin the rep, it kind of cancels out.
My TM only goes up to 10.0. Not fast enough for hard core sprinting speed work. But! If I put the incline up to 10.0 also, now its a quality rep. So, for example if I want to do 8 x 100m at 90-95% effort, that works.
For distance running speed workouts, the 10.0 is just fine for me. 12 x 400m is a good TM workout. As noted above, it takes a few extra seconds to go from jogging to 10.0, but after 0.25 miles, I turn it back down to jogging pace and it takes a few extra seconds of fast running to get it back down and its a little further than 0.25 miles. Good enough.
I only do this if the tracks are covered in snow. Otherwise, I have plenty of tracks nearby to choose from. If someone else is running, good for them. Usually its walkers. Depending on the track there are kids or high schoolers on the infield doing soccer or something. Whatever, I am always older than their fathers and sometimes older than their grandfathers. That makes me a role model as far as I'm concerned.