depends on your goals, if you want to get better than take the lessons at uni you’ll learn way more faster. If you just want to have a social fun time then go to the tennis night but you wont learn much. I’ve worked as a tennis instructor and done group lessons like you would take at uni and tennis nights. Nights just end up being adult babysitting, you match up players give them tennis balls hit a few balls but you just don’t have the time to give much individual attention so players dont get better they just have fun and meet new people. In a group you go thru a lesson plan and will get the attention you need to improve.