The 7750 is a rough and tough workhorse used in the majority of all 6,9,12 counter chronos not just IWC. IWC however sometimes uses higher grades of theose ETA ebauches.
If you like the 'tumbling' sound, which most WIS refer to as the rotor wobble....you can get lots of cheaper alternatives..Mido, TAG, EPOS, EDOX, Omega lower end chronos, B&M, Longines, etc....
Its odd that you like the tumbling sound as most WIS get a 7750 movt chrono as its much more reasonably priced compared to other higher end chrono movements like Lemania, FP 1185, Omega 3313 or 9300, Seiko 6S37 which are much more refined and doesn't wobble...
Whatever floats your boat but I personally disposed of all my 7750 based chronos coz the wobble bothers me and the fact that the hands move when the time has been set and the crown is pushed back in is not acceptable..
If I wanted a 7750, I would go for Junghans Chronoscope Max Bill which also houses a 7750... elegant, well finished and much more value for money compared to this particular IWC.
However the beautiful dial and tumbling sound that the 7750 movement makes is driving me nuts...