OCD home user here.
Proper distribution before using the OCD is a must.
If you have a mound on one side of your basket, spin the ocd and tamp you will still have channelling.
That said, IF you have done finger tapping/WDT/funnel swirl to distribute the grounds relatively evenly throughout the basket and THEN use the OCD, the results are fantastic.
When using this, my pulls look nearly identical every time-- espresso emerges as three streams, then converges within 4 seconds to one in the dead center of the basket
Waste has gone drastically down-- sink shots have become a thing of the past here, minus an initial dialing in of a new bag
Would like to note that I'm using a Forte BG-- filter burrs-- for these shots. In the past I've had difficulty regulating flow through the grounds with this burrset, channeling and drastically-varying flow rates have always hindered my espresso. The OCD has helped correct this.
The OCD has been worth it for me, in my limited home setting
Cannot comment on commercial use-- I simply do not pull enough shots to have the muscle memory for finger tapping/swiping down like many may be able to do
(see chris baca's OCD video comparison of finger swipes vs ocd)
Equipment in use: Breville Dual Boiler @ 6bar, vst 22g ridgeless, 58.5 flat tamp