I bought 2 of these to act as intake and exhaust fans on a rebuilt PC.
The fan surround is a fairly brittle, clear plastic which doesn't present a problem; each unit screwed firmly in place (helped by a tiny drop of washing-up liquid or petroleum jelly) but I wouldn't want to move or re-orient one after initial fixing.
I have one plugged into the motherboard and one on a molex, and there's no apparent difference in their performance. The cables aren't that long but the molex adaptors I was supplied with also act as 3-pin extension cables. Certainly, I could have plugged the exhaust fan at the top, rear of the case into a socket anywhere on the ATX motherboard.
I can't hear them over the noise of the PSU fan but then I wouldn't describe them as pumping out a mighty storm of air - what you get is more of a gentle breeze. The PC ran for 9 years without noticeably overheating so this doesn't particularly bother me as I just wanted a bit of air passing through the machine and not to have warm air re-entering it through the vent at the back (it's in a computer desk).
This fan is okay and good value at less than £3.50, but I'd want something a lot more powerful if I was trying to fix an overheating problem.