Buffer is a scheduler, and one of the best. It covers almost every platform, it's stable, and it doesn't pretend to do anything else. So the comparison only makes sense if your goal isn't scheduling, but finding clients.
The detailed comparison is on the Kast vs Buffer page.
Two different jobs
Buffer lines up your content over time: you write somewhere else, you paste, you schedule.
Kast handles what comes before and after. Before: writing in your voice and the score on four criteria. After: capturing the people who engaged, with their job title and company, and sending them to Lemlist, Instantly or a file.
The scope, stated plainly
Kast covers LinkedIn and X. Threads is coming soon. If you post on Instagram, TikTok, Pinterest and Facebook, Buffer does a job Kast doesn't, and we don't claim otherwise.
In B2B, that limit rarely matters: your buyers are on LinkedIn.
Content stops being a visibility expense and becomes a steady flow of contacts who already know you.
What you gain by switching
You stop judging a post by its likes. You see what's off before you publish, and you know who engaged afterward. Many keep Buffer for the other networks at first, while they see what LinkedIn and X produce.
To pick your time slot, the best-time calculator is free. For the full method, see post, measure, capture.