I hate this! Most of my clients find it totally ugly as well. Unfortunately every magazine is copying each other with this and polluting their pages. This is hopefully one of those things that will go away very soon. Where are the days you had to have Abercrombie styling
To get your products into the magazines you have to have this 3D thingy at this moment.
Don't waste your time with perspex mannequins, the back side will be garbled and the image even more ugly. All the contraptions give you issue with the form, unless you client doesn't mind about this. Especially the shoulder area is becoming a nuisance. Which ofcourse you can fix in PS afterwards and you probably will when the client rejects what you have done. Most of my clients would have rejected your example, I can already hear their remarks. Bottom is schewed, shoulders are square, underside of the sleeves is not straight, etc..
I do it shooting on a mannequin, shoot it flat on the floor and blend it in PS. Yes, your post production work takes longer but the shoot & styling will take a lot less time, even though you have to shoot twice. The results are also much better.
I also prefer life models, even if it means cutting their heads off (in the image) to prevent having to pay them more money.