I love my 8900. It has taken on anything I have asked of it. Any problems were mostly operator error, but I agree with Geri B that there may be a problem with the machine or the tech, if the problem isn't being resolved. Maybe you can do a trade-in for the 8900.
I did a lot of research before I bought my 8900 and 99.9% were positive. No machine is ever an absolute perfect fit. I've had a Designer I and a Pfaff before this and sold them. My 8900 does pretty much whatever most of the Berninas do and for less money.