I agree with Dave.
These tools will work better with interlaced material than progressive, but there is no substitute for high frame rate capture in the 1st place.
And I have had more luck using Twixtor than AE for the times I have had to use it.
If you don't require HD, or very high quality at all, then there are some interesting little compact cameras from Casio that can do 1000fps albeit at a lowly 224x56 frame size. 420fps is better at 224x186, and 210fps at 480x360. Check out
http://www.casio-intl.com/dc/ex_fh20/hsmov/ to see some examples.
