That deal comes in at a total of £695.76 over the 2 years (for the series X).
Now that we know that the Series X will cost £450, that means you'd be paying £245 for the Ultimate Gamepass (which would normally cost £264 across two years). The ultimate gamepass includes Xbox Live Gold as well which is, what, £50 for a year so £100 for 2 years? Throw in EA Access as well and that looks like a very good deal.
Not sure I have the time to benefit fully from game pass (whether ultimate or otherwise) but, if you did, that's an excellent deal.
I think I'm going to wait to get the Series X. I'd only play ED and The Witcher 3 on it which I can do now. The graphics will be better but I'm not paying £450 just for that. Hopefully by the time Bethesda finally release Starfield, the price will have come down (although there are bound to be other games that come out in the meantime that might take my fancy).