I bought the Sonic Frontiers SLF1 last year and have greatly enjoyed it, fun rolling tubes and as every review says, the world's greatest remote! I don't have experience with SQ with any other preamps on your list, but the SLF1 in my room doesn't sound too different than using my DAC's preamp capability, DAC being bel canto 3.7. I really wanted multiple balanced inputs to easily A/B DACs and needed balanced output as this was the main reason for buying a pre, to move all gear except amp to a side wall, which meant a 15'+ run from rack to amp.
Best of luck, let us know what you pick!