I bought this watch primarily because I was using my phone as an interval timer, but it was a pain to have it in view constantly, and the app crashed occasionally (which really screws up a crossfit type workout when you have to stop, start the app again, and then get back to it).

For that, it works great - I have it set for 60 > 20 > repeat - so I do my exercise for 60 seconds, max effort, rest for 20, 60, 20 - until I'm done. The interface is a little confusing at first, but they only have so many buttons to work with. For the price, I couldn't find anything better.

Other thoughts: I looked for a programmable watch that actually had two sets of intervals, that you could "link" - I do 10 exercises, and have a 120 second break, so ideally, the 60/20 would repeat 10 times, queue the 120 minute timer, you'd be able to set that combo to loop for 4 times (which is pretty much my workout). Not a huge deal, and I couldn't find anything that did that - if this just had a couple of more slots for intervals, I'd just be able to loop it (it would need 11), but it's not a big deal. I just stop it at 10 repeats, reset, wait 2 minutes, and start again.

Helps my workouts mainly on focus; I don't have to mess with a phone or an app, it's just a solid state device on my wrist that tells me when I'm done.