Mark I have both so hopefully may be able to help a little
the Aspira and the valez are considrabley different despite looking similar. The hood on the valez is detachable and uses four studs to keep it in place. Becouse of this the material between the should and the top of the hood does not have the waterproof pump liner and so could allow water in down your neck as can the fact that the gaps between the studs can blow out and allow water in that way. The hood on the aspira is attached and fully lined, but can fold down into the coller should you wish it. The hood on the aspira is also mountain cut so you could get a helmet underneith.
The aspira again is cut differnetly so it covers you arse and is comfortable with a harness, the valez design for high energy sports ( mountain biking and the like) is a shorter cut.
The valez has the single front pocket which can sag out if you have too much in and its not easy accesss with a rucksack on so the aspira has the compass pockets, and internalmap pocket and the main zips.
The aspira also has greater fit adjustments and the foam inserts in theback to make the heavier rucksacks more easy to bear.And it hs the pit zips and a full chin up zip and beard gaurd so that it can zip right up, the valez has a lower cut neck.
Hope that helps? I use the valez more than anything, but if I'm on the fell withabig sack or bad weather I use the aspira. Its also worth trying them on as the fit of the aspera smockdoesn't suit everyone.