DashCommand works pretty well. Interface isn't perfect, but once you use the examples to see how to set up custom settings it's alright. Stay away from cheap wi-fi OBD dongles. I had a Veepeak one that bent the pins on my car's OBD port. You might consider using an OBD2 extension and plugging the dongle into that. Some of them have a switch to prevent battery drain:
http://amzn.to/2mF6DrX
I'm now using a Bluetooth Kiwi 3, and the update rate with Harry's LapTimer is much faster than wi-fi. It's $99 vs $15 though:
http://amzn.to/2lyMxPo