I'd buy the one that had the negative carriers, and if possible, a lens or two. It's the extras that will run you more than the enlarger. Any of these, assuming they're in good shape, should be fine. I suspect the Saunders would be the best too, but again, condition and the other necessary tid bits you'll require need to be factored in. Make sure the condenser(s) are in good shape and are actually there! It's craigslist stuff.

If you can, try and find a photographer that is selling a complete darkroom set up. The trays, film washer, safelight, etc can all run into serious money (for me anyway) if you have to buy them new, or have to pay shipping on individual used items.
What he said ^^

If an enlarger is complete, works and has the neg carriers and lenses for what you want it for, and the price is right go for it, especially if it comes with all the other darkroom bits too. Don't worry too much about brands. Everybody promotes what they have and there are perennial arguments about diffuser or condenser, glassless or glass neg carriers, colour heads or filters. Seems everybody makes work what they have. Enlargers are cheap these days. If you really do end up with a dog, move it on.