Not just for Xmas...
I see the FX and the Glock itself as almost two separate instruments - there's a lovely, airy, almost string synth quality to the FX in the higher registers and it serves as a great pad in isolation. It can provide quite an organ like bass too.
The glock itself is wonderfully thunky in the mid register and more traditional glockenspiel further up.
Its a very versatile instrument; in fact I managed write a track (Like Clockwork by Feersum Endjinn) using only this instrument and some percussion (it's included in the demos if you want to check it out.)