I have 2018 350's and wouldn't have any other motor. They are flat-out fabulous. I can't speak for the reliability of 2010 year engines, however. Before you turn down the boat, I would talk to a qualified Yamaha Tech and get an opinion from an expert who works on them.
MY 2018's need a flywheel replacement after the engine logs 80 hrs between the 3500-4300 RPM range. Yamaha performs the service free of charge and it costs you nothing for the life of the engine. I've already had one replaced and it's nothing. they do it in an hour or so; I time it to coincide with my oil changes.
Again, I must repeat, your engines may not be covered by the same warranty my 2018's are; heck they may have not fixed the problem back then, but it would be worth a conversation. I would certainly investigate the 350's, but would certainly not black-ball them until your convinced they would be a risky purchase. They are a dream to have, V8 torque and the extra HP made it a no-brainer for me to choose them over the 300's.
I didn't agree to the 350's on my Marlin until I talked with Yamaha techs and the Factory itself. They assured me the problem was fixed and I haven't looked back.
