Url shortener or 301 Domain?

Hello guys. I want to promote my smartlink on social networks, but I'm in doubt which service to use. If I choose the 301 domain option, can't I switch the landing page to another one if the old one doesn't give results or is it permanent? Would it be interesting to use rebrandly if I want to promote multiple offers on the same domain?

shorteners are better in this case

use bitly or rebrandly

A URL shortener is an online service that takes a long URL (web address) and creates a shorter, easier-to-remember URL. A 301 domain is a domain name that is redirected to another page on a website.