solo vs buddy

I've seen quite a few things on solo diving vs the buddy system. but why does it always have to be between those two? how about something else that actually makes sense: what I usually do is group diving. no fixed buddy, but sure as heck don't go by ourselves. the group sticks pretty close together, no holding hands or bumping into each other. we can still do our own thing as long as we can see each other perfectly. the advantage is if something were to happen, we could just bang on our tank, and more than likely more than one person is there to help. which is always a good thing.

I would rather dive solo than in a group (and I don't dive solo).

Apart from hating the herd thing, it is almost impossible to keep track of everyone in a group (more than 2). If someone drops out for whatever reason there is a high probability that no-one will notice.

Buddy diving works. I would use it regardless of how many divers are in the water.

I agree. If you're diving in a group, you still need to keep a head count and keep track of the divers. Otherwise, you could still find yourself in a situation where the person in the back or on the fringe of the group runs into a problem. Depending on the vis and the nature of the dive, its possible that the person might not be noticed until its too late, particularly if they cannot, for whatever reason, signal for help.

I don't like to dive with more than three people in the group. Even then, we practice together and maintain passive contact with each other throughout the dive by using our lights or, in particularly bad vis, through physical proximity and contact.

... that I've dove with, there are still buddy teams withing the group. Basically, the buddy teams are accountable to each other and the group pretty much stays in visual contact. The exception has been whoever is actually leading the group may not have a buddy if there is an odd number in the group, In that case, the leader role is assigned to a DM or diver who is: 1-familiar with the site, 2-comfortable diving without a buddy and 3-has a redundant air system.
Personally, I prefer either a single buddy or no buddy. I've been the dive leader for a group and found it can be a pain the the butt to keep track of 6 other divers in low viz! I've also been part of a buddy team in a group and as long as the rest of the group are "good" divers (i.e. not messing up MY viz!) it can be OK. I'm usually familiar with the site, though and get together with my assigned buddy and the DM and we set a point in the dive where we split off from the group and dive our own plan ut: