It definitely depends on the congregation. It seems the only hard rule that they pass down in writing is that a bearded man cannot give parts on conventions/assemblies. Some elders take this to mean that a beard isn't acceptable at all. That's not surprising since much of JW doctrine is developed based on the formula of 'this rule applied to this small group, so it shows the principle that it should be applied to everyone.'
When you grow a beard, you'll inevitably get compliments from the guys who want to grow one too but don't have the balls, and you'll get passive-aggressive statements ("did you forget to shave?" "it looks like you have some dirt on your face." etc) from everyone else. If the elders are the iron-fist type, they'll probably try to make an example of you, but if you have a few elders that are sympathizers, it's possible that nothing will happen.
If you do grow a beard, memorize Mark 7:13 - "You make the word of God invalid by the tradition that you have handed down." Encourage anyone who challenges you to read the full account and find out who Jesus was talking to, and come back when they can state that they're not behaving just as those men were.
On a related, but slightly off-topic note, it's my theory that rules such as this are in place specifically to identify potential apostates. When someone starts to wake up to TTATT they're bound to start wanting to think for themselves a little. Even if they're not fully awake, but just see that the cult is making unscriptural rules, it's dangerous - those faithful in what is least will be faithful in what is most. If they start breaking the small rules they'll break bigger ones. The beard thing has the advantage that it takes active effort not to grow a beard, so it's natural to let it happen when you no longer have a strong reason to do it. Also, if someone stops going or fades, the beard is a sign to any friends that might otherwise think they're just going to a different congregation. In a sense, it's like an unofficial DA that most will recognize and will cause them to avoid you. It's all about maintaining the virtual cult compound - separating those that are in the cult from those who are out by means of small cues like dress, grooming and language. You don't have to physically separate people from the outside world if you can create the walls in their minds.
