Here, in Argentina i9300 stuck in Jelly Bean 4.3. (Official update OTA provided by Movistar phone company and manual with Odin in Sammobile) what i don't like about this, is that Samsung present the J1 with 4.4 kitkat, but the phone has 512mb RAM. Samsung give the excuse that is not going to update i9300 because it has 1gb RAM.
Gracias Rey David!!
Those low ram devices have a light version of touchwiz running. Samsung cant port this to the s3, since it would mean a "downgrade" of the device in terms of features, etc. Customers usually dont want that