I'll comment on the designer shoes I've owned (aside from what others have mentioned so far), for whatever it's worth.
Valentino- nice design but the quality is poor and you pay a LOT for the material/skin and the name. I have a pair of patent leather ankle boots, retail about $600, and they're largely glued together but the leather upper is nice. There is even one spot on them where the glue is already starting to come undone near the toe. As well, the quality and construction of the sole is only so-so. That being said, if they are only occasional use shoes (I mean, I don't use a pair of patent leather ankle boots everyday), the design and aesthetic are beautiful.
Jil Sander- There are numerous levels within the line, but any produced after 2001 or so aren't so great (the Lattanzi made Sanders were from the late 1990's and went away when Prada took over). The entry level Sander's (retail about $395) are really about $150 shoes with $150 of packaging and brand recognition. The upper-level shoes (retail $600+) are like the Valentino's... nice/exotic leather uppers with so-so soles. Sort of like how Mezlan will put out a $700 crocodile shoe with the same shoddy construction of its $150 regular line.
Helmut Lang- Like Sander but cheaper at retail and therefore cheaper in materials and quality.
Calvin Klein Collection- Produced by Zengarini, I was actually quite impressed. They're not Lattanzi, of course, but for a retail of $395 or thereabouts, they're nicer than my Sander's, Pradas, etc. Not as nice as Rossi's Gucci models, but still good and often obtainable at discount. Zengarini also makes shoes for Allessandro Dell'acqua.
Dior Homme- Produced by Buttero. Quality good for designer shoes but a style that is difficult to wear often. And, REALLY high price. I would recommend buying a similar style made by Buttero itself (retail about $325) which will give you essentially the same quality at about half the price.
Loewe, Givenchy, Louis Vuitton- All made by (I think) Stefano Bi. Probably amongst the better quality for designer shoes (in my experience), but with a retail price to match. A $595 pair of Givenchy oxfords won't be half as high-quality as a pair of $595 C&J's, but still they're not bad.
Marc Jacobs- Made by Iris SRL, which also makes for Galliano, Viktor&Rolf, etc. Neat styling but, like all the others, so-so construction. I've got a pair of brown derbies (retail $450 or so) that I love to wear out but are already looking worn and ragged after only a year or so.
Prada- All over the place for quality. I've got six or seven pairs of Prada and some have lasted me forever and others fall apart quickly. A pair of black chelsea boots bought back in 1999-2000 still look great after MANY wearings, but another pair of black derbies have been worn less than half a dozen times and look like shit. I think they use many different locations to produce the shoes, so it is hard to tell which ones will last and which won't. They all look great at first, but only time (and a few wearings) will tell. It is like their nylon bags, they have a "sport" collection (NOT the red-tagged Prada Sport line, but just the regular black nylon line), a "couture" collection, etc. all of which LOOK similar but use different materials. The sport collection uses cheaper nylon, cheaper leather, etc. and lasts about 1/10 the time of the higher line.
Of all of the ones mentioned, I'd second Labelking's Rossi recommendation, followed by Givenchy and then Calvin Klein Collection. Prada would then follow, but only if you got it on discount. At retail, I don't know if it is worth taking the chance. Jil Sander I'd recommend only as vintage that you can find on ebay with the nice, handwritten labels inside. Armani, I won't comment much. Every Armani shoe I've seen has been unimpressive for both quality and style and so I've never bought one.