Having worked with many PR/Marketing/Media brand teams I do not know of one group that utilized twitter client in any of their workflows -- they all used a mix of third party clients for reading and other integrations/clients for posting and managing conversations and ad work. Sure much of the API surface area for latter still works but there was a goodly portion of impacted folks on these clients that were the same people that were on the same teams that impact ad spend and brand usage.

I've never seen a PR/Marketing tweet from any of the bespoke artisanal apps (tweetbot, twitterific etc) Hootsuite, buffer are web apps, not for "ride or die" iOS nerds