Then please try to hear a better turntable if you possibly can. You can’t improve the sound once it’s been captured by your cartridge, as you surely know, which is why my earnest advice is to focus on the turntable, arm and cartridge rather than the differences between two phono stages. I’m surprised your Hi-Fi store friend hasn’t said the same.
You obviously know what you’re hearing because I’d expect the Moon to sound smoother and the Rega more exciting too. I owned the Rega Fono mini I recommended earlier for about 8 years, and you shouldn’t interpret ‘fine’ as any put down. When I ‘upgraded’ to the Fono II, which is much the same internally as the one you’re auditioning, it wasn’t particularly superior sounding, just nicer to use and with a pretty light-up logo. The MM stage in my Linn DS that I now use is better than the Rega to my ears.