I've tried the Apple wireless keyboard, Joy Factory Arpeggio and Verbatim folding keyboard and my favorite is the Joy Factory Arpeggio. The Verbatim felt like a kludge - creaky, flexy, uneven, etc. and was thick enough to offset the benefit of the folding design. The Apple, on the other had, was (and is - I use it with my Mac) brilliant in every facet except for one - size - it's just a bit longer and thicker in the back than I wanted. The Arpeggio is very similar to the Apple (although its build quality lags, unsurprisingly, behind the Apple) but it's 2cm narrower and 1cm thinner. Despite the 2cm difference in width, the key spacing between the alphanumeric keys is only 1cm less because most of the difference is in the far left and right keys (tab, caps lock, shift, back space, return, etc.), and as such the overall spacing doesn't really feel significantly smaller than the Apple. Key feel is outstanding - virtually identical to the Apple - and the Arpeggio has iOS specific keys which the Apple does not. I know 2cm narrower and 1cm thinner may not sound like a lot, but it's the difference between the keyboard fitting in my existing sleeve and not:
Sleeve:
Arpeggio in sleeve:
Apple "in" sleeve:
Sleeve:
Arpeggio in sleeve:
Apple "in" sleeve:
