Please help! I know nothing about diamonds,& usually picked what I like rather than what is the better diamond for the price. I know what I want...A 1ct Princess cut solitaire.
Well, I'm sure we can help, but we need to know a few things - mainly what type of metal the mounting will be in as this affects the color range you can use, and what clarity you can live with. This is important as quite honestly any stone over SI2, and even some I1's, are totally clean to the naked eye when set even if they look like a train wreck under a microscope. This bothers some people as they know there are flaws in there even if they can't see them, some don't care as long as it looks good on thier hand.
What's your price range?
The price range for a G-VS, ~ 1 ct princess appers to span from 3.5k to 5.5 k. The variation is not straightforward to explain. For example, not all VS1s are more expensive than all VS2s. The quality of the cut (as defined either by AGA standards of straight light return) is one uderstandable reason I found, and well cut princesses (premium cuts) go around 4.5k. Less expensive stones come with basic certs only and no aditional guarantee for cut quality (which does not rule out hunting for a nice stone).
Phoenixgirl's idea is actually the way to go around here: post options and you will surely receive detailed feedback on them. For example, the two stones in her post illustrate quite well what extra depth does to shrink the aparent size (i.e. LxW or diameter): while the second stone is a nice choice, it's 75% depth does not help it show it's "size" (cts. weight). This is some concern with princess cuts, and I am really fond of those around 65% depth... as long as they show reasonable light return. The first stone is surely closely to my hart. Of course, your prospective buyer's choices will most likely attract much more detailed feedback