The pros of being an cosmetologist are many. The first would have to be the fact that there are so many different avenues one can take once you have acquired a cosmetologist license. You can work in a salon or you can start your own salon. You can specify what area of cosmetology you want to work in or you can do a little of everything. Another pro is the satisfaction of knowing that even if you move on to do something else you can always fall back on your cosmetology training to make some kinda money. The last pro I will say is the partial comfort of job security going into this field provides. People will always have hair and will always want it to look nice. There are many more pros but I won't bore you with them all.
The cons of being a cosmetologist are dependent upon what area of cosmetology you enter in. One general con that I can think of is that in the field of cosmetology one has to constantly self promote and sell their selves. You have to constantly push to keep an good amount of return customers so your income never takes a huge dive.