which should I install, firefox or firefox-esr

[積丹尼 Dan Jacobson]

Which should I install, firefox or firefox-esr?

They both say:
Description-en: Mozilla Firefox web browser
 Firefox is a powerful, extensible web browser with support for modern
 web application technologies.

But one is much more fresher,
$ apt-cache policy firefox firefox-esr
firefox:
  Installed: 47.0~b5-1
  Candidate: 47.0~b5-1
  Version table:
 *** 47.0~b5-1 990
        990 http://free.nchc.org.tw/debian experimental/main i386 Packages
        100 /var/lib/dpkg/status
     46.0.1-1+b1 500
        500 http://free.nchc.org.tw/debian unstable/main i386 Packages
firefox-esr:
  Installed: (none)
  Candidate: 45.1.1esr-1+b1
  Version table:
     45.1.1esr-1+b1 500
        500 http://free.nchc.org.tw/debian unstable/main i386 Packages