CBT/DBT/ACT are the big 3 therapy modalities that have the most research validating their results. DBT is good for certain mental health issues, especially personality disorders but is also useful for mood disorders. DBT groups are fairly common and can be the preferred method for administering treatment depending on your needs. If it was something recommended to you by a medical professional for a specific issue that seems relevant to what DBT addresses, or it seems like something that might help you with what you're struggling with, then by all means pursue it. Each practice/practitioner will vary, but as a treatment methodology it is scientifically sound.
DBT takes a long time (like, a year depends on the patient) and can be quite intense but the results are very, very good. Wait times to get in it can be long, if you have the opportunity and need it - jump on it.
