I still am curious as to what the difference is besides the nodes being able to signal to the ecosystem in a slightly easier way through a GUI that they wish larger blocks. Is this it?
I think there are a lot of misunderstandings about BU. The main idea is dirt simple:
- Current situation: blocksize cap for the network is set by miners/nodes converging on either Core, XT or something else by downloading and running Core, XT, etc.
- With user-selectable blocksize cap: blocksize cap for the network is set by miners/nodes converging on either Core settings, XT settings (BIP101), or some other Schelling point by adjusting their settings to do so (BU can be made to default to Core settings, if you want)
There's another "oversized block acceptance depth" feature LovelyDay mentioned that is envisioned may come in handy, but it can be turned off anyway so I'll focus on just the "user-selectable blocksize cap" aspect. This is all it is.
"user-selectable blocksize cap" aspect -
1) So I fire up 2000 nodes, all selecting 200MB as cap.
2) I make the miners belive this is the prefered block size.
3) They all start producing 200MB block.
4) I fill up the blocks for the next 10 days
5) Bye bye 75% of all network nodes
6) I pretty much run the network