The main difference lies in the fact that SegWit aims to restructure the block space to allow more transactions per block, while Unlimited aims simply to raise the blocksize to allow more transaction.
You seem to be misstating your summary.
Bitcoin Unlimited attempts to change consensus thresholds. That's no minor or inconsequential change.
Mate, could you please explain me ? What he said is false you said. You did not talked about SegWit so his description is right, isn't it ? And for Unlimited, they want to change how much is required to apply an hardfork or a softfork ? That is what I understand by consensus thresholds.
I am a layman too in a lot of this, but I do recognize that frequently people who are selling Bitcoin Unlimited are of the same camp as the XT and Classic folks.. and they are continuing with their various attempts to change bitcoin's governance.
They are obsessed with it. So they try to frame a lot of technical arguments and appeal to folks that change is good, blah blah blah... but in essence, what they are proposing would undermine bitcoin in a lot of ways.
They have hardons for hard forks, and making all kinds of proposals and threats to hard fork and also they want to do these kinds of hard forks with levels of consensus that are much smaller than 95%.. I doubt that folks are going to follow them, but they do succeed, to some extent in their ability to block improvements to bitcoin by suggesting that you are either for or against seg wit which is opposite BU.. blah blah blah.
If you change the consensus thresholds to 75% or some amount that is much lower than 95%, then you run a considerable risk of producing two chains.. and yeah, probably once you do 75% consensus then you would set precedent and continue to make decisions with relatively low consensus.. which makes changes much easier (but not a good thing for something, such as bitcoin, that is so potentially undermining of various status quo financial institutions).