No point hooking it up to a phone that will eventually be old technology in 4-5 years time when this thing is more purposeful and records just about as much things, including short and long term fuel trims.
It can do all the things Rev can do, plus it can also hook up to the v-manage and f-manage.
I've used Dynolicious on the iPhone. It has some of the same features as Rev (recording G forces, 0-60, Quarter Mile times, etc.) and doesn't cost much. I think it was $10. Doesn't plug into your car though, so no reading codes.
Seems to be pretty spot on, so long as you calibrate it properly and lock it down on the car somewhere (I just grab some masking tape and tape it down so it won't move). It's a lot of fun to use.