Very user friendly indeed. Previous versions were less user friendly, but allowed to read more raw statistics/details. This can still be done at least with console utilities, I don't know how to do this with Carman 0.7.

Carman comes with a simulate option. This way, you can try it out without buying the hardware.

Some nice integrations with map software and statistics like refuelling would be very neat -- I agree.

ELM327 BlueTooth 30 GBP was a pretty good deal (for a 1.2v). Bought via eBay UK.

BTW, in the normal interface with the meters you can see different meters by clicking in the middle left or middle right (almost like a gesture like when browsing in Fennec).