I have the tx600a and it's been an absolute nightmare. This is my first machine as I'm 16 and only been stringing a year. I was pulled in by the price, an electronic machine for £400, bargain! Bought it and within 6 months I had to buy 2 totally new clamp bases, they were automatic but now I've got the normal ones.
My advice would to buy either a top manual machine, or if you see a cheap electronic go for that. I won't ever be buying a Pro's pro machine again!
That's just my opinion.