are the cleaning agents in esso/petro gas enough?

[[d]ealer[o]f[t]he[f]uture]

esso and petro advertise their fuel already have cleaning agents in their fuel that clean car engines, so do I really need to buy those fuel cleaners from CT?

for example those ones:
http://www.canadiantire.ca/assortments/product_detail.jsp?FOLDER%3C%3Efolder_id=140847439 6669651&PRODUCT%3C%3Eprd_id=845524443279631&ASSORTMENT%3C%3East_id=1408474396670271&bmUID=1142293896827&assortment=primary&fromSearch=true

[nx2k]

i don't think they advertise as cleaning your engine, i think what they said was burns cleaner opposed to black fumes, that's still not clean
buy some cheap red fuel injector cleaner when it goes on sale at crappy tire and put it in every few fill ups