All I want it something that will say why the **** the "check engine" light is on. That alone is worth $70.
Well, it's worth at least $20, which is what most OBD2 readers go for in the store. Even cheaper on Amazon. They've been out for, what, a decade now? Or, just stop at your nearest auto parts store and ask them to scan your vehicle for you (they obviously would much rather you scan than the service station, because then you're more likely to buy parts at their store) almost always at no charge.
The other features are what you get for the other $50+. If you just want to figure out why your check engine light is on without having to tell the guy at AutoZone "No, I don't want to buy the bits to fix that right now", buy a cheap scanner off Amazon and be done.
From a high-level point of view, I'd love to see this succeed. However, for a gadget nerd to get excited about it, Automatic needs to prove its hardware is capable of reading realtime ECU data (ie, the data displayed by $80+ single-purpose hardware OBD2 readers, such as specific engine timings and misfires data, etc). If it can just get that data sent across to the phone, beating the Actron devices is all a matter of software, and I'm confident software written on a general-purpose device will quickly surpass that built into single-purpose hardware (as has been the case in every previous similar situation over the past 30+ years) and Automatic will have a rabid customer base.
Of course, another option if you want the more techy aspects of it (as opposed to the slow-down / auto-call-for-help-in-an-accident features which seem pretty much completely divorced from the OBD data stream except maybe for braking measures) is to get a $15 OBD2 bluetooth dongle at Amazon and a $50 display/logging app in the app store (but it sounds like you need to jailbreak your phone to get the bluetooth OBD2 dongle to connect!). In the non-jailbreak world, though, it sounds like that $15 device needs to be replaces with a $150-ish WiFi device (and you need to have your phone ad hoc connect to its wireless, which might cause issues with your carrier's data connection, etc).
Overall, I think Automatic has a good start. Keeping things simple is a great strategy here. If they can build out (or partner with one of the existing iOS OBD display/log software houses) their software they can really make a killing in a market whose leaders have long been in complacent cash-cow-milking mode.