I'm 100% with Gavin in any decision he makes. But we've actually started making progress in countries where Bitcoin was once illegal, how do we rebuild these achievements and what will the ultimate consequence be for Bitcoin & XT?
Bitcoin-XT is running, right now. It's the same blockchain. It doesn't create "XT coins". The proposed code change would only take effect when 90% of blocks were compliant with the XT changes. This is not the first time we've branched. IMO, this is much ado about nothing.
For those who are new to things, note that the first >1mb block (or otherwise incompatible) block XT produces will release what I call 'XTaint' into the wild. That would be the 25 block reward (the 'coinbase'.)
What a possessor of XTaint (or it's derivative) can do is to mix a little in to a spend to themselves. The spend will be invalid on Core so their Core holdings are unimpacted, but will be valid on XT so they can run it right down to an exchange or pawn it off on some other XT user.
Of course the converse is also true. Coretaint can be used by XT users in the same manner. Choose your side wisely if you are going to play these games, or just sit on your hands for a (long-ish) while.
Likely many others will join in the games so thing become what I call a 'battle royal'. The weaker ones (and maybe others) will employ various kinds of tricks such as analyzing alternate forks and artificially legalizing transactions tainted with other coinbase, or simply monitoring for spend activity on other chains and devaluing them.
Some chains might distribute some 'free taint' which _must_ be mixed into future spends. Some might force deep storage to be dug out and re-spent for various reason.
Some chains might switch to merge mining in hopes of using the extreme sha256 for backing while hoping to protecting against POW attacks. Some might tweak their POW to limit the danger. Some will go temporarily or permanently central for oracle service to guard against attacks.
There will be exchanges where people can bet on outcomes and play the various spreads. Even different spends within a chain will be valued differently depending on whether they are 'universal' or not. Spends consisting only of coin prior to 'the event' will command a premium. So long fungibility.
This, and likely countless things I've not thought of, are what lies inside Pandora's box, The lid can be pried off by forking without decent consensus, but eventually it probably will be pried off anyway so it would not be fair to blame Gavin for the event but simply the timing thereof. There is a lot of value in the blockchain and a lot of people trying to get that which currently is controlled by others, and a lot of others trying to protect what they have buried within. It's going to be fun.
Obviously these are just my predictions. But, FWIW, I predicted that BTC in the single digits could be a very good buy among other decent calls over the years. I also predicted that UTXO's buried in the blockchain would retain a value (if not grow) in an event such as I've described, and that was one of my rationals for taking the position I did.