--based on the admittedly unscientific, anecdotal reports typically found here at Neurotalk, that there would necessarily be much to choose between the two--I actually think you could try them both, although you should take them separately from each other. Some people have good success; some, not so much--response is rather individual. (I would take R-lipoic acid, rather than alpha lipoic, for many of the reasons listed in our threads--the R-faction is the one biologically active in the body, allowing you to take less of it, etc.)

A good 1000mcg/day dose of B12--methylcobalamin preferably, and that taken apart from anything else--would also be a good idea.

In terms of profile, lipoic acid has the longer history--it has been used in Europe for many years, on prescription, as a treatment for diabetic neuropathies primarily, as it has glucose regulating as well as antioxidant properties. Acetyl-L-Carnitine is also a potent antioxidant and is supposed to help repair/prevent mitochondrial damage, which is increasingly being thought to be a major factor in some neuropathies.

I don't tend to recommend specific brands, but you can look for these in on-line stores (which I think are more comprehensive in terms of choices than most of the brick/mortar stores). Many of us use iherb, swansonvitamins, vitacost, and others--all you've have to do is put these into a browser search box.

Many small fiber neuropathies are thought to be ischemic/circulatory in nature--more obviously in the case of diabetic or metabolic ones and more subtly in the case of autoimmune ones (the autoimmune attack may be to components of the nerves themselves or to the blood vessels or supportive tissue that feeds those nerves, as in the case of some ANA-mediated conditions). So anything that helps support circulation wouldn't hurt and might help.