What do you think about this engagement ring? Which cut would you choose?

I think it's fine to show him that picture, but I would not buy that particular ring since most of those mounts are only 4 prong instead of 6. The difference being that if a prong breaks on a 4, you lose your diamond, if one breaks on a 6 the stone will be loose but will not fall out. Show him the picture, but he really should go to a local jeweler not a chain or mall store. Why, because those types of stores will try to sell him more than he can afford, they make most of their money off of finance charges. A local store wants to see you get the most sparkle for your money. In other words, you get a nicer or bigger diamond for the same amount of money. Notice in that ad that the $300 does not include the diamond. The diamonds shown are to my eye about a 2 caret stone and are very high quality so it would be $300 for the mounting plus that quality and size stone would be about $6000. Go with him to a local jewelery store, just to look at real stones and mounts, you can point out ones you like and he can go back later to select the exact one, that he'll give you.