That one does seem to have better reviews. Too bad there are only 3 :( any more input on this new one posted then?
Hard to answer your questions without a little more information...
What are the specs for what you currently using to run FFXIV? Is $800 the limit on your budget or is that just what you have to spend right now? What else do you need the PC to do?
There are several reasons I ask these questions:
First and foremost, XIV is changing and Version 2.0 is nearly a year out from now. Any suggestions for something to run XIV are only based on what we have now and speculation on what is to come then. If you'd come out and said that money was no factor and that you could spend anything on a PC it might change the suggestion a bit, but it's never wise to make an investment based on speculation.
The other reason I ask is because in the long-run it will probably make more sense to upgrade what you have to a comfortable level for you to play in the meanwhile. If you don't have a PC at all then of course this changes things, but you have to remember; technology changes constantly. Something you pay $800 for now could possibly get spanked by something a year from now that costs the same, if not less.
My best advice would be based on what you currently have. If you can't play at a comfortable level then my guess is it would be better to spend a little to upgrade. Waiting sucks, but you'll be able to make an informed decision on what to get based on what we will know by then instead of speculation. You also get the added benefit of being able to save more for your budget and components will be better so you'll get more performance out of your dollar.
If you don't have anything now or XIV isn't playable, my best suggestion is still to wait. If you just can't wait and you do decide to get something anyway, realize that your budget now will barely get you to your goal of high settings(if that) and will possibly require an upgrade or two in a year to maintain that. You'll likely end up spending more than you should have for the same performance.
Either look at your best options for upgrades(post what you have so we can give you an idea) or just wait it out. I can't (in good conscience) tell you to spend money when we don't know what we'll see when Version 2.0 is released. Based on your budget, this is an investment for you and it's never a good idea to make investments based on speculation.