It all depends what data you are after. I used the zeitronx one and logged AFR(wideband) TPS, Boost, RPM, EGT and 1 user input. I plugged in my AIT.
My next one will be a PLx R500 with the added feature of logging and hearing-on-speakers knock + it has a real time G sensor to measure the bhp/torque.
All these can be used as stand-alone on a standard car.