Bit-x is the oldest one which count post from bot and pays. But it is hard to get accepted by them for campaign. There is also another one yobit which pays daily actually pays every 3-4 hours. Recently coinoindex is also paying daily at rate similar to yobit rates.
Coinoindex is a "product" of coinomat, both of them use the same bot.
But it was just different at their backend to identify the participants on each signature campaign.
As the coinomat manager said that their will soon announce the avatar signature and they will use bot for counting the post i think this will be the first avatar bot to count the posts.