Depends. Both systems as configured run about the same. don't know where others are getting there info but the kt133 is not problematic at all. It maybe even one of the most stable VIA chipsets out there. There is no 686b southbridge to worry about either. Granted, there maybe certain brands with this chipset ( budget boards ) that are not the best but that is do to the motherboard makers implementation of the board and not the chipset itself. This being said the bord you have curently is not a bad board either but does it allow for overclocking? How much Ram will it support? Did you plan on sticking with the p3 733 or upgrading it eventually? This is the thing to consider most, right now you can get a 100 fsb athlon 1.2 gig processor and put in the Asus board for <$100.00 where as a mere 1 gig p3 will run you $172 or more. If you plan on sticking with the processor on either board than as others have stated stick with the p3, if a CPU processor is in your future then a trade may be in your best interest. Resale wise, the p3 combo is worth more, perhaps renegotiate a trade with cash involved ( ie make the trade and get $30.00 cash as well then use this towards a better processor)
A little bit of knowledge is a dangerous thing!