I can't recommend any of those, they all seem to have cheap power supplies. I have never heard of Frontier as a PSU name. I have heard of Spire, but nothing good. I think the 3rd computer does not mention the PSU.
Of the 3, the one with a Spire PSU has a "Spire CoolBox 500W" so I searched for that.... but I see it's just the case and I really have no idea what the PSU is.
However, they all seem to be under $400 US Dollars.
If you need to buy one of these, get number 2. It has a 6770 and a good motherboard, and you can upgrade the PSU (first) and the CPU (second).