we had a manual validation system at one point due to getting a huge amount of spam bots on here, uksc may have a different reason for requiring manual validation I dont know.
Manual validation was a complete pain in the arse for admins on here and was not a great new user experience but it did solve the spamming problem. We have since implemented some new user sign up tricks which stop the vast majority of spam bots signing up.
On the ease or difficulty of use, it depends on what you are used to. People find vbulletin very easy to use and I suppose it is but I think a lot of it has got to do with the fact that so many high profile forums use vbulletin it has kind of become the norm. I would love to move this forum over to a new up and coming forum software that we have been looking at for some time now with great interest.... haha.... I think I will hold off though as history has taught us over 10 years of tgtt... members fear change