It depends on what I am looking for at the time but in general a good quality render with examples of the features of the product.  For example, if it is a scene I want to see the expanse of the scene, if it is a building with internals I want to see each of the rooms.  If it is a character I want to see both a close up of the face and a full body render.  I want to see the options too.  For example I will not use a characters eyes if all of the options have burnt in reflections.   I can, and do, change the eyes in such instances so I might still buy but the price becomes a bigger factor.

I want to see the a list of the other items used in a promo.  If it is a character I want to see the hair used in the promo and the clothes.

Big turn of for me is poor materials, if they are I rarely buy unless the model is good and also cheap, that way I buy and work on changing the materials.  I am not going to pay top notch if I have to work hard to make it useable.

I do still sometimes risk a purchase even with a poor promo and have had some pleasant surprises.  On the whole though I buy from form a small nimber of vendors i know will give me good quality products. 

I know any tutorial purchased from Fugazi1968, any character from Mihrelle, Freja or Godin, any item from Fabiana or Vyktohria and any scene from 3-d-c is gong to be high quality and my runtime is full of their products.  I have other favorites but than iI have been buying content for a number of years but the vendors above know how to put a good promo together.

 

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.