I think that you'll feel more confident and better informed by visiting a number of different strata management agencies, large and small, and then deciding for yourself which one to nominate in your CTTT application.
What I like about small agencies is you generally get to speak with your potential manager from the moment you walk in their door, so you can gauge how confident you'll be in handing that person basically dictatorial powers to run your building. This is what led me to choosing my new agent, because I got to know him as a person and it didn't feel too corporate, and I visited him several times before deciding to nominate him.
However unlike with larger strata management agencies, if you end up not liking your agent you can't call their boss to complain because they are the boss. They might also not be members of reputable strata management organisations to pressure them in case they're doing something wrong, which is a benefit of reputable large agencies.
With large agencies you'll likely speak to a nice spokesman and not the specific person they'll assign to run your affairs, so you might not really know who you're really handing power to unless you ask to speak to the potential agent before deciding you'll recommend them to the CTTT.