Abit's BX6 was designed with overclocking in mind, but unfortunately there wasn't enough time spent on compatibility issues. Nevertheless is the BX6 a step in the right direction if you compare it to its predecessor LX6. The compatibility is a lot better than it was with the LX6, which had problems with many PCI and ISA cards and also a serious keyboard problem. Abit is trying to make a big deal out of the data buffers, but I can't help and stay unimpressed by this. Data buffers are normally required as soon as the board comes with 4 instead of only 3 DIMM slots and most of the other boards have them as well. The other point of the data buffers is that they can slow the board down, whilst covering timing problems with the RAM. Some good designs can do without this and actually run faster.
Abit forgot a few features, like e.g. the 'SBLink' connector.
The BX6 shares the ISA network card incompatibility problem with a lot of other boards and with some work of Abit's BIOS engineers this problem should be fixed pretty soon. On the RAM side the board did very well. You can plug in pretty much any PC100 SDRAM and it even runs some PC66 SDRAM at 112 MHz. This doesn't even require any settings change in the BIOS setup, because there are no RAM timing settings to be adjusted.
The board does not only offer the selection of FSB clocks from 66 to 133 MHz in its well known 'CPU SoftMenu' , but also the option of adjusting the CPU voltage. Abit proudly presents this as 'SoftMenu II', forgetting the fact that this new feature is a great tool for killing your CPU. The BX6 is a board for people who like experiments and who like overclocking to insensible areas. The missing RAM timing adjustment in the BIOS setup makes it easy enough to crank up the FSB to crazy heights.
All in all the BX6 isn't a bad board at all and for overclockers it could be the number one choice. However, if overclocking doesn't play the major role, you can find better BX boards.
The BX6 didn't make the overall recommendations list because of its compatibility problem in combination with low to average performance and the lack of any special feature.