Browse host isn't reliable at all. You might be unable to browse a host then 10 minutes later the same host can be browsed. You may see 30 files when browsing a host, 10 minutes later you can see 100 files from that same host.
You have more chance of being able to browse hosts who have chat enabled, but even then it's very random as to who can & can't be browsed.
Users who are firewalled are very hard to browse.

There's no option to enable/disable browsing.