this is a difficult question to answer as it really depends on so many variables (individual aspiration, type of educational institution, curriculum, quality and philosophy of the individual educators, etc). that being said, i will offer my perspective.
my particular experience started at a small 2 year college that was backed by both Pratt and Corcoran, though i began attending in only its second year of existence so the curriculum was being developed as we attended (this turned out to be a benefit in hindsight). i graduated with an associates and then enrolled at the University of the Arts the following fall. over that summer i began assisting a high end commercial photographer in Philly about 25 hours a week (which i continued to do throughout the remainder of my schooling). after graduating with my BFA, i continued assisting and began working in a commercial lab. after about 2 years i was invited to teach continuing education classes at my original school and often interacted with the degree students there. eventually i was invited to become an instructor at the University of the Arts and just wrapped up my 13th semester there. i have essentially participated in all sides of the questioned posed.
much has changed since i first began attending art school with both the photography industry and the industry of education.
i would say above all else, it depends greatly on the individual as to whether formal education in photography is worthwhile AND what that individual's aspirations in photography are. after that, the type of institution, its curriculum, and the quality of its educators can have a profound impact on whether the investment in that education is worth it.
if the assumption is that the individual has the highest aspirations in photography (whether it be in a commercial or fine art venue), then yes formal education can be extremely valuable....BUT only if the quality of an institutions curriculum and its educators are on par with the individual's aspirations. there are many talented students who wash out because they cannot handle the rigors of pursuing a successful career in photography and there are many institutions that will provide an education but that education may fall well short of preparing the student to successfully enter the world of PROFESSIONAL photography.
aside from that, mentorship, camera clubs, and continuing education classes may provide minute benefits in the short term but in my experience they very rarely provide the type of information that would propel someone towards real long term success as they are typically run by individuals with limited knowledge, experience, and success. camera clubs are particularly suspect and are pretty well despised by reputable professionals and educators.
the reality of photography (imo) is that it is a complex and diverse subject that simply takes a lifetime to master. the very annoying trend these days (which has been exasperated with the advent of digital) is that photography is easy and can be learned quickly. so many people out there want near instant results whether it be a client or an aspiring photographer. sub par photography is easy and happens often. masterful photography takes a tremendous amount of knowledge and experience and is becoming more and more rare.
so in the end it really depends on what you feel you need to be educated in and what your end goals are. if you just want to learn some new tricks then there's probably a website out there or a class you can take. if you want to be the very best photographer you can be, then the education never ends and you should be actively getting it from every venue you can possibly gain access to.
