Every phone is a bit different in regards to its WiFi range (as well as range of its other antennas like cell network for that matter). The HOX seems pretty comparable to past HTC devices I've owned.
Depending on whats software version your device is currently on, you might see a slight difference if you update it. But it won't be a drastic change. Might even get worse.
That just tells me your hboot and radio number, not what software version (ROM) your are on. The hboot and radio are very recent, so I can only guess that your ROM is, also. So I'm thinking outdated software is not the issue.
I also can often get multiple WiFi networks for neighbors houses. Suburban area, so the other homes aren't all that close. It could be you have a defective HOX, such as a broken WiFi antenna. But no real way to know that unless you can get ahold of another HOX and compare.
Everything is very up to date, so I don't think that software is the issue (although the latest AT&T software and radio might make a slight difference).
I don't know what you mean by "same type phone", that is too vague to mean anything. Is it an AT&T One X (EVITA) or something else?