What makes them worth the extra value should have been the question I asked.
The cheaper one will overclock and work just as well as the others. If you dont need the additional candy then buy the cheaper board. Geeeesh!
Not arguing, but I'd like to point out that Enthusiast boards generally have superior voltage regulation, higher quality componentry, and much deeper and finer control available in the Bios. Even though they may be the same brand as a more mainstream choice. And you definitely pay a premium to get it. So IMHO, the real answer is "it depends on how much you're overclocking." Most any board will go a few steps, and if that's enough, then great!
Having said that, if you're intending on (for example) pushing a 2.4GHz Q6600 up to to 4GHz on air then i'd stronly opine you should spend the money if you expect to be successful. And the longer you intend in running that kind of setup, the more you should expect that rule to apply. Meaning you may be able to push a cheaper setup to the same, or nearly the same, level. But I wouldn't expect it to last.
THough of you're not overclocking at all, then just count how many PCi slots and whatnot that you need. Then buy a decent quality board that fits the bill. The cheap stuff often works... But the couple times I've tried have ended poorly. And - again IMHO - in the long run it's better to overbuy a little to ensure reliability.