Interesting ... although the "you can connect all your buttons directly on the Jamma board" line is rather misleading ... it appears that you have to connect buttons 5 and 6 directly to the Jamma harness (to M/11, d/26), rather than to a seperate terminal on the encoder.
That could be a pain ... I'd much rather have seperate terminals for non-JAMMA connections than have to patch into a prewired harness.
I also noticed that they don't mention the amplification of sound issue, which is kinda important.
Cheers.