I would also love to hear your experiences with the Antpool prioritisation service: what kind of transactions end up being successfully mined? I have used the service only a few times so far.
Prior to recent spike of unconfirmed transactions (around 2 months ago) I was able to accelerate transactions that contained only 1.5 sat/B in transaction fees but it's no longer the case (either due to the fact that it became a known service or they change its structure completely).
Nowadays only those transactions that underpaid by around 100+ sat/B (
based on this website) are being included in next blocks that they mine (considering those have been accelerated through Antpool), meaning they prioritize transactions based on their fees (on their queue list) so it wouldn't be that useful (if it's urgent) for majority of transactions that use a very low fee (those with less than 250 sat/B) since the list gets updated frequently with other added transactions.
This is correct...
Due to people posting the link to that page on bitcointalk and other public pages, i can only assume their acceleration page gets spammed by hundreds of people that want to cheap out on their fees and push a 1 sat/byte tx in antpool's blocks.
I can only assume antpool uses their mining node's prioritisetransaction funtion. If all prioritised transactions get the same fee_delta, it would still lead to a fee bidding war within the prioritised transactions in their mempool.
Even worse, if their (hypotetical) fee delta is, for example 50 sat/byte, a transaction with a 1 sat/byte fee that gets prioritised would still only have a virtual fee of 51 sat/byte, hence have little or no chance of being put in antpool's blocks, since there are enougn non-prioritised transaction that have a much higher fee.
I have no idear if this is the way antpool works, but this hypothesis seems to be more or less consistent with what i'm seeing trough the use of their accelerator page.