I own a Wersi Abacus Duo Pro and from first hand experience I can say without question the Wersi is the best built best sounding arranger on the market. Don't expect any cheap plastic in the Abacus, the frame is made from heavy gauge steel with real wood sides. The sounds, features, and user interface of the Wersi rival anything available from Korg, Roland, Yamaha, Technics, and Ketron. Only the new Korg Oasys offers similar features but until I play the Oasys first hand I can't say if its comparable or not but it will be very difficult to rival the Wersi.

Yes, the Wersi isn't cheap but you are definitely getting a well built instrument with incredible sounds (OAS 7 will feature almost 1 GB of sounds as standard), extensive features, lots of inputs and outputs, and upgradeability for your money.

I thought I was crazy spending that much money on an arranger but having used the best that Technics, Roland, and Yamaha had to offer only to be disappointed by them, I can honestly say the Wersi surpassed my expectations and continues to get better with each OAS upgrade. Reliability has been rock solid and those who doubt the stability of the OAS system likely haven't used it.

I would urge anyone who is serious about arrangers and can afford to buy the Wersi to check it out, you won't be disappointed.