It's a fair point that it's a chunky price for any title either way! Also worth highlighting that both like-for-like and cost-for-cost you won't find Gundam Seed any cheaper in HD in the UK on launch. Right now the US pre-order price is $224.99 (£172.59 at today's rate), then shipping to the UK makes it $262.50 / £201.36. That's not including any customs charges you could get hit with too.I'll admit, I saw £199.99 and thought "It's a shame to miss out on the original series, but I guess I'll wait till next year", then saw the early bird is £119.99 and thought "Actually, that's not so bad. I'll probably plonk down the money at that price". I guess I now know a rough price at which I'm willing to buy a collectors set (of something I really enjoy and have been having fun collecting).
You're not only getting the same discs and extras (coded to Region B) for £81.37 less at the same time as the USA (before any customs), you'll be getting collector's packaging in line with the other UK editions and an artbook as well (which will be the same dimensions as the box for us not an A4 - which I am not sure the US one isn't too based on packshots).
Folks mileage may vary but at that kind of price difference, if it's a Blu-Ray sized book there too then you'll need to weigh up how much that is worth to you !