Sometimes yourself is the only sane person to talk to!

Anyway, my SLX has treated me very well for a long time, I just need a transmitter with a variable gain since my bass is louder than any passive but less loud than some actives. The PGXD14 looks like what I need, or the ULX but, that is very pricey for what I need it for. I don't know what the advantages or trade offs there are between digital and UHF though?