I used a TC-760LC for almost three years. Stock with the cheap wallwart is just as quiet as my battery powered RSA F-117 Nighthawk. So while in theory the battery powered unit should be cleaner and quieter due to it being off the grid, in practice (at least in my setup) there is no difference. What the Nighthawk has over the TC-760LC is dual mono, which gives it a slight edge. The Nighthawk has better loading and gain options, which makes it a good fit for just about any cartridge. That said, the TC-760LC worked great with every cartridge I threw at it: Benz Glider, Benz Wood M2, Benz Copper Reference, Ortofon Kontrapunkt A, Ortofon Jubilee, and the ZYX Airy3.
I will, without reservation, recommend the TC-760LC to anyone who needs a phono preamp and has a budget of less than $800. You get a lot of performance for $73. You can find better performance at way higher price points...but IMO even then the extra cost is not justified on performance alone. Take it from someone who used one every day for years. Or don't.
--Jerome