Well to tell you the truth i haven't recieved my escort g-timer GT2 yet as ive ordered it from the states and still waiting for delivery. i havent seen a bad report on it either or the gtech. what i liked about the gt2 was that it gives forwards sideways and braking g results.
also its a bargain at $50 compared to the $300 for the g-tech. the way ive read it is acuracy is determined by the importance of inputting the right weight pitch ect. and to calibrate it.
the gt2 auto calibrates when you press the 'start run' button on the remote and will hold 10 runs in memory.
saying that i also read that the g-tech has more involved software and can memorise the input data for upto 4 cars.
either way they are both cool units and should be a good if not dangerous thing to have. just make sure you play with it away from the boys in blue!