My 1st stringer was an Alpha Pioneer. I had it for almost 14 years and the only problem I had was the spring snapped (sheared would be a better term).
Five years ago I decided to buy a newer one and went with Eagnas because (a) it was considerably cheaper, and (b) it looked to be the same as some of the other models I was looking at. Today I'm replacing the Eagnas and going back to Alpha (http://tt.tennis-warehouse.com/showthread.php?t=437813
), mostly because I'm stringing more racquets than before, but also because the Eagnas is a POS.
In the 5 years I've owned it, I've had problems with the gripper (first the string would slip, then I had a problem w/ the ball bearings), the spring snapped 2 years into it, and I've had multiple problems with the clamps not locking. Oh, and customer service has been poo-poo (I pilfered parts from my old Alpha to fix a few problems).
Consider yourself slapped...