I know someone has already asked about silent partner, but has anyone had any bad experiences from them, becuase I have talked to several dealers who sell all ball machines EXCEPT silent partner, due to customer complaints. However, from the feedback on here, it seems like a good investment to me. Can anyone give me more details on the quality of this machine, becuase I am deciding between a NEW silent partner (with spin capability) or an USED tennis tutor 2 (with no spin). The only reason I am considering the tennis tutor is due to the fact that I hear they are very reliable. Any feedback would be appreciated, thanks.