Recently added front chains on the B2320, to complement the rears. The lack of steering traction during snow removal was a significant safety issue in our case, having nearly slid into the roadside ditch a couple of times - but we get a ton of snow and have a long driveway with moderate hills.
While Kubota does not recommend front chains, I have not heard of a single case of anyone destroying their front drivetrain as result of front chains. Has anyone? For us, the added safety of better steering traction is well worth the risk of damaging the drivetrain - the drivetrain can always be repaired.
Haven't had a chance to use the tractor with the front chains installed, so can't comment yet on the efficacy.
As others have mentioned, front weight helps too.