My Sony RM-AX4000 is about 5 years old and the volume and channel keys are starting to fail. Since Sony no longer makes this unit anymore, what would be a comparable remote to replace it? Right now I am using the Sony RMVLZ620 which will do all my macro functions and everything else the 4000 could do, but I miss the LCD touch screen. Has anyone had any experience with the Acoustic Research ARRX18G XSight or any others at a reasonable price that would compare with the RX4000?