I have participated in this topic in wet pixel and
http://www.damnam.org/forums/viewtopic.php?t=48
I am of the view that for a new diver or less than about 200 dives, that a buddy most definately is beneficial. On the other hand, for mosre expereinced divers, having a buddy, who you probably met 5 minutes ago, is more of a liability than diving alone.
Case 1
Went down on the Hardeep for a fun dive inbetween a training dive, and in our group an instructor tooka tourist down for his first wreck dive. Well, it was not well timed, and we all know just how bad 'extreme' currents can get on the Hardeep. On the bottom, instrutor signals he has an issue, and asks me to stay with the tourist to at least give him his moneys worth on the wreck. I look at the tourist, and his eyes are as large as golf balls from panic. Never the less ( yes , bad decision, we all make them ) I decided to accept, mainly because this was his last dive before returning. Now here is my point. a) I spent all my dive trying to get him hold on to the line as he was being constantly blown away by the current. b) The guy was breathing like a steam train and basically on the edge of loosing it c) if I did get in trouble, would he have the capacity to help me ?
Case 2
Another case, a guy who was in my group ( again, just met on the boat ) paniced on the surface, spat the dummy ( regulator ) started gulping water ( putting air in your BC helps stay on the surface ! ) . Ended up having to resolve the issue my self (with a NX-80 housed Nikon in the other hand) as the incompetent dive master could only meakly say ' calm down '.
Point is, for me there has been very little benefits / upside, and on the contrary, I am placing myself at risk by being around these people as sooner or later they will complicate my dive, and potentially bring me down in thier panic.
I know it is a selfish view, but survival is not something to be treated lightly, and minimising risks is the best road to staying alive in this sport.
Another point is I enjoy photography. Having dived with friends, we always seem to loose each other in 5 mins due to visability problems / being focused on a certain subject. ( try to think of your buddy when you have a whale shark / manta in front of you )
Thirdly, complacency kills. If you are relying on your buddy to get you out of a sticky situation, you liable to be a statistic one day
Would be interested to see what your views are on how having a buddy will help. ( ok, point taken, with a good buddy, and maybe being stung by a stone fish, there might be some up sides )
FYI, I dive with fully redundant second tank ( 20 cft) with seperate regulator, so blowing an O-ring is not an issue
If you are new to diving definately use a buddy.
If you have a super buddy who follows you like a puppy dog, sure, dive with a buddy
if it's " Hi, I am greg, can I dive with you ?" you most likely safer alone if you have enough dives under your belt ( in my case, I only started solo after about 600+ dives....... ( yes..... some will say "what, only 600 ! )
Finally, for those of you who have expereienced the serenity of solo diving, and the peace / tranquility which goes with it, having to ever 2 mins check on the existance of you buddy breaks the bubble. ( have to ahve been there to know the feeling )