Acrylic is probably the most popular substrate for permanent in-store free-standing displays, counter displays, and brochure holders. There are definitely some draw-backs, being first and foremost, the brittleness of the product. The material has great structural strength keeping it straight/upright over relatively long lengths or heights, but the corollary of this is that it lacks flexibility and malleability. In a store environment, it means that customer knocks (and let's be honest, staff knocks too!) can lead to cracking and edges breaking.
Some retailers may also be put off by the material's sustainability. Acrylics are in the same family as PVCs. They are generally not recyclable (a Class 7 plastic) nor are they substantially made from recycled material, and the manufacturing process involves the use of highly toxic raw materials (see this link for more on the properties of acrylic).
So why is it so popular? The material is extremely versatile (see some of the images below), highly attractive (its clarity, its edges - particularly if flamed) and it's structural strength (see above). The verdict: for many retail displays, you can't beat acrylic.