I flashed mine recently, for what I paid I think it is a great deal! I paid for my Audi TCU tune 500 and there are zero customization options and one map only.
I first did stage 2 and after a couple of days stg3. In the past I always felt that delivered power/tq was not 100% according with the engine rpm, now seems to be on pair. I haven't done any draggy comparison to before and after so I can't say some actual numbers but gear changing are extremely crisp, there is no faster than this. I been waiting for almost two years (since I got the car) for a TCU tune, not necessarily because of the gear changing feeling slow, that was pretty good to begin with, but my concern was that of needing increase clutch pressure. Everything else I got it is a bonus
Also, stage 3 it is the way to go, D mode really feels no different than before while on Sport you get the best optimizations. Everything feels as smooth as before, there is also the option to customize pretty much everything if you don't like the way OTS maps are including setting up a higher rpm shift point if desired. I haven't touched any customizations yet and I probably never will.
As for the cable, I used BimmerGeeks Pro cable, first time flashing took about 8min and second time 2min