I did one single cruise and hated it. Never again. My impression of the single cruise experience is that it is very much a meet market where people are looking more to hook up than to socialize. I found the atmosphere to be "bizarre" to say the least.
If you want to be in an environment like that (which is o.k.) then a single cruise is for you.
If you want to meet people without the s*xual/romantic expectations, you will probably enjoy a solo cruise or a group cruise without the word "single" in the group's name a lot better. There are all kinds of theme cruises you can take that will give you the best of both worlds. Perhaps you can look into what types of groups are hosting cruises during the time you want to go. Think of your hobbies/interests and then do an Internet search combining your hobby with the word "cruise". You may be surprised what will come up (i.e., "country/western cruise" or "christian cruise")
As for solo cruising, as a single man, you will be adopted by other people and groups on the ship and will have to struggle to spend time alone.
Either way, enjoy.
(cruzin' solo by design)
Freedom ('09), Imagination ('08), Victory ('08), Destiny ('08), RCCL Navigator ('08), RCCL Majesty ('08), Glory ('07), Liberty ('07), Fantasy ('07), Destiny ('06), NCL PofAm ('05), Fascination ('04), Victory ('04), Fascination ('04), RCCL Voyager ('03), Fantasy ('99)