Tippmann Boss as the best entry-level leather sewing machine. They are currently on sale from the factory at just about what used ones are selling for on Ebay.
Based on the same recommendations, we drove to Fort Wayne rather than having one shipped, so I could see how these work. I talked to one of the techs who assembles and repairs Boss stitchers, and he showed me how to set up and use the machine. He recommended a thinner foot and a 10 pack of needles, both of which were thrown in for free. Being out of state, I also avoided sales tax. He also said that he grinds the front of the thin foot off for better visibility, and he can get within 1/8 inch of an edge or raised section.
The Boss is a completely manual machine. Stitching is done by pulling an arm similar to a slot machine, once per stitch. The arm has a handle like a bike brake lever to lift the presser foot. Stitch width, foot pressure and thread tension are all adjustable. I practiced on some scrap leather, and quickly figured out how to get decent results. I then stitched a holster I'd started to hand sew and abandoned. Even though I had to carefully monitor the stitch placement because this holster had some of its holes pre-drilled, it was still incredibly fast compared to hand stitching. Back stitching can be done by either turning the material or by lifting the presser foot and manually aligning the needle for each stitch. You want to backstitch on both ends of your line--the beginning is best done by reversing, so the holes are properly spaced.
I'm nearly certain that I'm going to be very happy with this stitcher.