The Swing is a good machine. No real downside compared to the other cheap dropweight machines, except it's slightly more expensive (than the Gamma X-2, Kilppermate, and Alpha String Pal). Like those machines, it's a bit slower than a crank or electronic machine, and the flying clamps may be a little less precise than fixed ones due to some unavoidable twisting. That said, I still think you can do a decent job with any of them with a little care.
The SP clamps are just fine. No slipping at all if you adjust them properly, and that only takes seconds. They are all metal, so probably a step up from the plastic ones that come with the Gamma. Klipper uses all metal clamps that are obviously modifications of common vise grip pliers. They look kinda clunky to me but a lot of Klip owners like them.
The SP Swing comes with a full 660' reel of a basic synthetic gut. It's OK for learning on, but if you're buying the stringer to experiment with other types of strings, you'll probably never get to the end of that reel. It's good enough, though, for stinging the racquets of friends or family that aren't really picky about strings.
It's a bit better than both the Klippermate and Gamma X-2 because it has a quasi six-point mount instead of the two point one that the Klip and X-2 come with. It's not a true six point mount, with four contact points outside the frame, but instead all six points are on the inside of the frame. That spreads out the strain over a little wider area, so it may hold the frame more securely, but it's not really what most folks think of when referring to a six-point mount.
The Swing has a clutch, which means you can smoothly (and quietly) adjust the grippers without having the reposition the string, if you don't hit the horizontal point with the arm on the first try. The Gamma X-2 has a ratcheting gripper that does the same thing, but in discrete clicks instead of the smooth, quiet action of the Swing. The Klippermate has neither a clutch nor ratchet, so if you don't get the arm level, you have to pull the arm back up, reposition the string in the grippers, and try again. Klipper owners say they get used to this quickly, but I think I'd find that a major annoyance.
No starting clamp is included. None of the stringers at this level come with one standard. While it's a nice-to-have, the truth is you don't absolutely need one, and many experienced stringers never use it.
Sorry, I don't know what replacement clamps might be better. I'm happy enough with the SP clamps as they are, and see no reason to replace them.
