Get the basic not the pro.

Bothe the apps (basic and pro) are good. using the pro gives you the additional "complex" routine option which lets you add more interval cycles to a set, however, the simple routine option lets you repeat the set, while the complex does not have the repeat option- a big negative. Furthermore, I think if we had the option of changing the number of intervals to 3 or 4 (not only low and high) that would have made the the top exercise stopwatch around.

Rayman A about Interval Timer Pro, v2.5