Diki,
I owned the BK-7M - liked it a lot and it sounded really great. I sold it because it was difficult for me to use live. I bought the BK-5 and returned it after only 4 days. I was very disappointed in that it in NO WAY sounded as good as the BK-7M. Functionally it was just fine and the keybed suited me. I recorded about 20 songs with the BK-7M and doing a side-by-side comparison of styles and sounds was very revealing. I had no complaints about build quality or button layout- just the overall sound. NOTHING like the BK-7M. My advice for folks is to buy the BK-7M and a really good controller with lots of buttons to assign things to.

Deane