I've bought this casing for a PO Tonic as I think the bare PO's feel too fragile for frequent usage. As there is no specific casing for the Tonic (or other newer model operators) you're automatically stuck with this general model, which doesn't have the exemplifying symbols on the buttons like the model specific 'pro-cases'.
Although the build quality is decent I think for almost 40 euro's it's too expensive of a peripheral, but as this is teenage engineering it is to be expected.
My biggest gripe at the moment is that older, cheaper (29,- euro), specific casings like the CA-12 are discontinued, so if you have a PO-12 and want pro-case protection you're stuck with this one.