70/30 in favour of alone. I've been on the big group rides, and they don't do it for me - too much inertia / prevarication / group dynamics on the actual ride. Although post-ride the social side in the pub or cafe is obviously better than solo. Lucky to have the occassional ride partner to break things up.
Really it boils down to who you are, and the social / work circumstances of you and your buddies. Accept that sometimes you're a Billy and just get out there when you can. Often though if you ride alone you are more approachable out on the trail or at cafes, and I've had some good conversations with total strangers this way.
Also riding alone tends to be more about being introspective and finding new trails and getting happily lost, where being with others I personally tend to push the risk side of things a bit more. OK accidents happen, but the only time I've ended up in A&E has been on a group ride showing off.
The magazines must be tied by their insurers as they do tend to be negative towards solo rides, but bet anything that their staff are as varied in social make-up as we are on here.