really there are only 3 issues that have cropped up
1. dead pixels that affect certain carts (and there is a fix in place now)
2. Voltage issues on MV1F and MV1FS main board that cause reboots or problems reading the CF card (temp fix of simply turning down the 5V line with a permanent solution being worked on now).
3. compatibility issues with the 4-slot and 6-slot main boards particularly when using the unibios (with a permanent solution being worked on now).
Yes these issues suck but they only affect a sub-set of the people who bought the cart, and soon there will be solutions in place so that 0 people have problems with their carts.
A big part of the reason Darksoft got so much support for his MultiMVS cart with people waiting to buy his cart when there were others available is because of his fantastic track record of support with his previous products.
The CPS3 Super BIOS, the STV Multi, the CPS2 Multi, the F3 Multi have all enjoyed fantastic support from their launch up to and including the present, so even with the above problems no one is worried that they wont be solved.
The CPS2 had some problems when it first launched too, but it didn't take long for a solutions to be developed and distributed to all owners of that hardware. And even years after it's initial release new features have been added at no cost... that kind of dedicated support breeds confidence in future products.