With Foobar, they do tell you that you'll hear no difference between players. This is right from their web site.
"Does foobar2000 sound better than other players?
No. Most of sound quality differences people hear are placebo effect (at least with real music), as actual differences in produced sound data are below their noise floor (1 or 2 last bits in 16bit samples). foobar2000 has sound processing features such as software resampling or 24bit output on new high-end soundcards, but most of the other mainstream players are capable of doing the same by now."
I can hear differences between players, so I stopped using Foobar. A statement like that says to me, that they're not even going to try for better quality.