Love riding solo, love riding in groups. Each has their own benefits.

Group rides can suck when they don't leave on time, are slow, are too fast, stopping because others get flats, breaks that should take 5 minutes take 15, stopping to regroup, not knowing/trusting the other riders ability to ride shoulder to shoulder with you, to name a few. They are great because it's a nice, fun, relaxed ride, and an especially great way to learn new routes without having to look for landmarks or street names and worry about missing a turn.

Solo rides suck because, well, u r alone. Mechanical breakdowns are on you, you have to stop for every flat tire they can be monotonous, you can't draft, etc...

Each type of ride has it's time and place, and I enjoy both.