What synths are you using in each program?
The obvious answer would be that you like the sounds of the synth in Reason better than the synth in Home Studio.
MIDI data is only a description of a performance, it does NOT, as has been explained countless times, contain any audio information. In order for you to play back a MIDI performance you must send the information to a MIDI compatible device and THAT is what generates the audio that you're recording as a .WAV.
Hope that makes sense.
Ted