If the fake ones look just as good at the real ones to you then you don't know anything about diamonds at all.
There are excellent fakes out there these days, and my jeweler friends recommend them. And most of the diamonds on the regular market for the average Joe are pretty crappy at best. Often floor sweepings with occlusions, poor color and even sadder clarity. The best you can hope for is usually a G, and maybe SI if you're lucky.
Heck, I have seen a D, but I think it was in a museum :)
If I could have a 1 carat 'real' diamond that was the average one carat 'real' diamond out there or I could take that chunk of change and buy are really good something rarer....
a real black opal (not doublet), a good purple grape tanzanite, a real estate Khasmir sapphire...
I would.....and have it set with the really good fake diamonds around it (which I have done and will continue to do).
In my experence, there is way more pleasure in purchasing the other stones than there ever will be in buying any diamond.... almost all other gemstones, you can find the best of the best...... Diamonds are rarely at their best when real....