Back to the original question.... Graph comparisons between tuners.
Graphs are great, they give an indication of flat out performance and shape of the power curves but what they don't show is how well the car drives.
During development we made 80+ different maps for the N54 BMW engine, they all made similar peak power and torque and the curves very similar but some were great to drive, others were terrible with snappy throttle response and mid range flat spots, some had very eager low rpm boost which would cause a surging feel, some would work hideously badly with the auto box, but great on manuals.
Back on the day when the Vaux Z20LET was all the rage, we had 2 maps that people could try before they paid, a high power map (boost brought in later and linear throttle which meant the throttle had to be used with high rpm) for the bhp number chasers and a high torque map (lots of low/mid throttle power and much better as a road car) for people that wanted a really quick car in the real world. We often flashed both onto the car for testing without telling them which was which, everyone preferred the high torque map, many refused to believe it made less BHP.
We have lots of customers that have both ours and Revos TFSi software, both make similar power curves but very different to drive, Revo has lots of power at low throttle, ours don't (unless the customer requests it) some preferred Revo, Some preferred ours.
So the power graphs are only a small element to look at when choosing a map, unless there's a huge difference in numbers.