I did it last January and the paper work is a bit more complicated and you require 2 copies of everything instead of just 1 copy for a retirement extendion .
Also you are placed on a 1 month underconsideration stamp to allow all the checks of your application and a home visit from Immigration to be completed .
The only real benifits are
*****
0 to be seasoned instead of
*****
0 , but it can be withdrawn immediately your passport recieves your extension stamp as long as its back in 2 months before renewal .
You can also apply for a work permit it without leaving the country if you get a job here , with a retirement extension you cant .