I've listened to the leak two times now and really like it a lot, patiently waiting to properly dissect the new vocals. But this video clearly shows the one thing that I find very odd about this version, that Robins first two notes are kept from the old solo being combined with Slash's new one via a very strange cut and paste job. Surely the had to have been a more coherent way of putting that solo together if those first two notes where so important?
It might just be because I'm so familiar with the old solo and that's why it sounds so odd, but it almost sounds like it was live mixed and the engineer left the wrong track playing and changed it a second to late (which obviously didn't happen but illustrates how it sounds).