to answer your question on how much time and work does it take to make such character that you linked. it really depends on the person's skill and how quick he is, my estimation would be it would take around 6-10 days, maybe even more. again it depends on the person and how good he is.

characters are much more difficult because you have to know anatomy well to be able to produce a realistic character.

i've noticed with artists that on average it takes them between 3 to 5 years to reach professional looking models. (i'm talking purely about characters here)