Whether they're out 2 months or 2 years I think its more important how they teach anyway.You can have a great atcer whose knowledge is huge but unable to pass on that information.
True, but practical ATC skills (as opposed to the theory side of things) are very reliant on continual practice. Being taught control technique by someone who hasn't done it themselves for several years is far from ideal. It doesn't matter how good their teaching technique is if they aren't teaching you what you need to know.