Gear drives with the fixed single gear like the Milodon ones are great, but costly vs a chain. Once you pay for a gear drive you can transfer it to another engine later if you wanted to.

The Milodons do make some noise, but it's not loud like the old Pete Jackson floating gear drives. If you have a healthy exhaust sound it will mostly cover up what noise the Milodon style produces.

I think if I was going to use a chain I would get a Rollmaster or a Pro Gear set. You can find complaints about any type of chain set, but those seem to come up as good most of the time.