OTM has a habit of picking people who chat on forums frequently (I've seen in the past). There are those who would do a good job as a tester and respond to issues. Sadly, those people are left out in the cold (usually) because they care not to post a gazillion messages on forums. Good Luck to those that have gotten in.
not always but it might be a little true.. Beta is designed to mainly help and improve the game. although it probably unfair for some but those who spend time helping community on forums are might be a little favorable because support can clearly see that person cares enough to improve the game and provide feedback. But its not always the fact because in the past i seen many people with low forum post count be in beta. Its like saying:
Person X: has 1000 post but majority are " +1" "Yes" "NO" "Bad idea'
Person Z: has 100 post and they all well made and spend time analyzing the topic and providing a lot of feedback.
which one would be most likely trusted to test an area that OTM spend at least half a year working on. The one that put no effort into his posts or the one that spends time explaining his opinion.