If I had the cash and was a self flyer for business or pleasure I'd do it in a flash. For those considering it I highly recommend not trying to just be a VFR PPL on it. Use the aircraft and go do an IR if you don't have one already. It will a) make you a better more accurate pilot, b) capable of using a 109 to the full and c) likely reduce insurance premium depending on your hours. Also gives you some time with an experienced 109 driver next to you while you get comfortable.
If it's not been thought of maybe sell the share and an additional 5th 'share' for the same amount thereby having a rainy day fund for when parts are needed. Extra equity in the group and allows your 505 a bit of funding if insurance goes up. Just my thoughts though.