Reccomendation for WAV / MP3 joiner?

vbimport

#1

I’m looking for a program that can seamlessly join MP3 and WAV files. I’ve tried a few, but the ones I have used so far either aren’t totally seamless (i.e. gaps between tracks still) or have a UI that is just simply difficult to use. Can anyone reccomend a joiner, preferably free?
Thanks!
Baral’heia