In overclocker circles it's the only real thing, Abit's BH6. The reason for this is certainly its stability, but the main success of the BH6 is based on its 'SoftMenu II', giving you the chance of changing the core voltage of your CPU.
Now how is this possible and why don't other board members do it? Since the days of the Pentium Pro, Intel thought that it would make sense if the motherboard could adjust the core voltage for a CPU automatically. After starting the system, the motherboard checks a few pins of the CPU and detects the voltage, so that nobody would have to adjust it with jumpers, dip switches or in the BIOS setup menu. This is a very convenient as well as safe solution, you don't take the risk of frying your CPU for any reason. Intel does not want this to change, so most board vendors comply and stick to the specifications. It's rumored that Abit had to make a 'trade' with Intel, they promised not to make any Super 7 boards so that Intel still supplies them with chipsets although they ship SoftMenu II.
It's also well known for a long while though, that raising the core voltage of a CPU can improve its stability at clock speeds that exceed its specification. This trick has often been used with Pentium and later Pentium MMX CPUs, and you can still be successful with K6 or K6-2 CPUs. The only problem is that once you exceed the specified range of a CPU, you can just as well damage it. Raising the voltage does also not necessarily have to lead to success. Due to the higher voltage, a CPU gets hotter, because the power dissipation increases just the same. Thus it can reverse the beneficial effect of the higher voltage and your CPU does still not run at the higher speed. When raising the voltage you need to cool your CPU as good as in any way possible. This cooling issue is misunderstood by most of the overclockers out there. They buy fans and heat sinks of crazy dimensions, but finally they close their computer case and nothing has improved. It does not help placing huge heat sinks and fans on the CPU unless the heat can get out of the case. You will get a much better effect when leaving your heat sink as it is, but placing a large (and hopefully quiet) fan the way that it blows over your CPU and then OUTSIDE THE CASE. This cools a million times better than having a monster cooler on the CPU in a closed case.
The Deschutes core is supposed to run at 2 V, so this is what SL2W8 gets by default. Intel's specifications give you a range of +/- 0.1 V. Thus 2.2 V are already way over the limit. Please consider that 2.2 V may sound little, but compared to 2 V it's an increase of 10%. The Pentium usually ran at 3.3-3.5 V and I guess you wouldn't have felt that great, running the Pentium at 3.6-3.8 V. So be careful when raising the voltage to 2.2 V or even higher.