I prefer both...
Our local community bike shops do a great job of having set group times. There are so many levels of riders that you always seem to get better and know there will be people ready to hammer down. Riding with better riders will always make you better...even though it sucks to get popped off the back.
I also like to go out alone and just "play". Do some hill repeats or long flats...just doing what feels right for that givin day and enjoying the ride.
I think both styles are good...one for the physical and one for the mental. I think my power has come from group rides, since you can't control what is happening, and my endurance is from my solo and longer rides.
I commute so all my everyday riding is solo. On weekends I keep my own pace, go my own way, do my own thing. I don't want to get it a group with the ego factor so I'm solo on weekends too.
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Lead, follow or get out of the way.
I agree with you! When I go out with a group theirs always one person that doesn't follow the program. So I understand what u mean about the ego thing and riding At your own pace.