Files where only the lowest subband has been encoded (switch: --bw X, where X <= 689) will not decode with mppdec (1.01j) while the Winamp plugin plays them fine. Mppdec reports a "broken frame". Practical relevance is null, admitted, but somewhere there is a flaw in the decoder which imho should be able to decode all properly created mpc files.
I have allready mentioned this bug in another thread.
Files where the two lowest subbands are encoded decode fine both in winamp and mppdec, producing identical output (except the least important bit; should be a matter of dithering turned on/off) so no worries there.