Take the compressor off, Fran. Listen to the patterns without it. Just leave on the Standard EQ preset, and you should be getting apples to apples.

TBH, I don't think there's a LOT of difference in the drum kits (if any). Those samples are pretty small, not a lot of gain shortening them. I think that some of the keyboard Tones, however, have been squeezed a bit, data-wise. This is not unusual for Roland (or most manufacturers) when voicing a BOTL product with the voices from the TOTL...

One of the advantages of recording to the built in recorder is that it bypasses the output circuitry (I think...). So, if you have a BOTL BK-3, which might not have as good a final output circuitry (it uses a TRS single output jack, like some of the BOTL Yamaha's), you should still get a pretty good sound direct to the recorder built in.