I regularly do sessions with some good buddies who play guitar, Saxophone, and keyboards...it makes a difference, to be sure. I always learn something from these collaborations.
Still, I prefer to work alone...I guess it's a control thing(as well as a better profit margin)...but there is no doubt that having another musical POV is valuable.
Ian
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.