Tablet/smartphone DashMeter

Hi all..

Id like to try an tablet/smartphone dash board...
I found DashMeter Pro as an option, and some others, like rfdisplay, and im sure there are more of those..
Id like to hear from you if you are using any, which one you find most usefull, good working..
Im not so much in computers, I noticed those are bluetooth, wifi, or USB conected tablets to PC, so, is this something I need to study a lot, or its doable by an non-computer-freak somebody?

And finaly, is it worth trying and eventually buying something like that, even if its not a big invesment, if its unusefull, its waste of money, right?

Thank you for you thoughts and suggestions.