Try using EVR_C/A and bicubic scaler in MPC-HC.
Video playback isn't black magic. The basic idea is to demux/split, decode, pp and render. if you're seeing a big difference, the luma level is probably set incorrectly or something like color space conversion went wrong or you are seeing the differences of post-processing(or renderer).
PS: MPC/MPC-HC, ffdshow/ffdshow tryouts(CCCP), they are all ffmpeg based.
PPS: I read that Win7 media apps prefers Windows' Media Foundation codecs over any DS filters. However I never tested/verified it since I use neither WMP nor WMC.
*PPPS: 64-bit filters allow you to use them in 64-bit apps. That's about the only thing that matters.