I've never trained in a class setting, but I have ways trained with a partner or alone. My girlfriend is huge into powerlifting so we train train together 6-days a week, and I have to say, she's honestly the best workout partner I've ever had. We push each other and motivate each other, and we are each there to keep the other honest when one or the other isn't giving full effort. Only down side is she is really short (like 5'1"), so we do a lot of adjusting of bar height between sets of squats, overhead press, etc. since our gym doesn't have a monolift or similar.
Rant summary: a consistent partner is my preference