If you haven't already, check out the comparison Matoniz does of the Neo and Custom on youtube. He does a lengthy demonstration of both (Neo dark traditional sound; Custom lighter somewhat more responsive). I believe it's more contrast than say between ADAMS E1 and E3.
I think depending on your own personal tastes, going from any pro horn to another can be perceived as an upgrade.
Arnold (Arnie) Williams
Sterling Virtuoso Euphonium with Gold Brass bell (Capitol Pops Band, Capitol Pops Tuba Euphonium Quartet)
Yamaha YBH-831S Neo Baritone Horn (Joyous Brass, First Baritone)
Yamaha YBH-301M Marching Baritone (Ophir Prison Marching Kazoo Band and Temperance Society LMTD)
Yamaha YEP-830 Xeno Bass Trombone (Sacramento Concert Band)
Euphonium: DW Heritage 4AL (main); K&G 3D (Ophir Prison Band)
Bass Trombone: Ferguson M Series Jeff Reynolds