I'm not much of a talker while riding but I do enjoy having company riding the same routes. Our area is not flat so my group rides tend to be cat-and-mouse play - I fall behind on the climbs and make up on downhills/flats. Playing chase is fun. The group rides are best if they are "destination" rides or if people will hang around post-ride to socialize; but on the bike it's mostly business.
I do enjoy solo rides where I can set my own pace. If I want to stop and fiddle around with my lights, drink water, take off a layer, ... I'm not holding up a group. Or if I want to see how fast and how hard I can go, I don't have to stop to regroup. Trying to ride along with a slower rider is practically torture for me unless it is somebody I really like.
Peer pressure tends to result in me doing things that aren't in my best interests too.
It's also nice setting my own schedule and not having to drive 40 miles to ride my bike 35 miles at too-darn-early in the am.
Long story short: One or two group rides/week; one or two solo rides per week.