I had a play with it in the shop... tbh I do like the look of it, and no doubt from the reviews it's a good stove, but I just wouldn't buy it. Why? If I'm going very light with a gas stove I take a F1 lite, lighter and a titanium mug (total 148g w/o gas), for a nice simple cooking (well, water heating) when I don't mind the weight I take a jetboil... for me I just couldn't see a gap for the eta express. It seemed a bit fiddly to set up, it's more expensive than the jetboil, it's roughly the same weight as the jetboil... the only real advantage I can see (unless someone else can find one) is that you could maybe cook an egg or something in its lid. Personally I prefer the plastic (and non-rattly) lid of the jetboil.
Now if only they'd made a slightly smaller, lightweight titanium version of the jetboil (using something like the folding head of the crux for example for a smaller pot), I reckon they'd have a real winner on their hands
edit: regarding weights whereas ukclimbing lists it as 470g primus puts it as 418
http://www.primus.se/Templates/Pages/3_cols_white_middle.aspx?SectionId=5888