Class or Private? There are advantages and disadvantages to both group class sessions and private sessions. If you have the choice, consider your personal requirements and preferences.
Classes are frequently less expensive than private sessions. They are offered at specific times, generally for a flat fee for the entire series of meetings, and there is usually no refund for missed classes. There may be several classes at one level offered, and this gives you a choice of times and instructors. There will also be a variety of people and dogs involved. The topics and schedule are normally set, and time to address specific problems might be limited.
Private sessions may vary in cost from moderate to expensive. Time and length of sessions are generally flexible. Many are on a pay-as-you-go basis -- others may involve a contract for a specific number of sessions, payable in advance. There is less opportunity for doggy socialization, but instructors may sometimes use their personal dogs for demonstration and interaction. There will likely be more opportunity to address individual problems, and breed tendencies can more easily be considered than in a group situation.