Well, overclocking is not really risky of you stick to moderate guidelines. Yes, and XP2500 (in this case) even though they are locked past week #39 from AMD will still overclock to XP3200 levels - and yes - you get the exact same performance, sometimes more. If you did decide to overclock, you would want the XP2500 "because" it is on a default mutliplier of 11x (as is the XP3200) so all you have to do is raise your FSB to 200, then usually raise vcore a tad until you achieve total stability under Prime95 and 3Dmark, and memtest86. Rasing vcore brings with it more heat, however you can offset that buy using a good heat sink fan, and have several good case fans.
Your friend that had the Asus may have had revision 1.2 (the older one) and additionally, his problems may have been stuttering audio or jerkiness in games easily fixed "if" you know what your doing or know someone who does). also earlier Asus 1.2 versions, and even 2.0 had bios issues (corruption) just as the earlier Abit's did. both the Abit and Asus run much better with newer Bios releases and better revised boards (2.0).
One thing you can do is get it locally if you can, that way if it's bad, or you dont like it you don't have the hassle of online RMA. I would go for the Asus locally, and make sure you get revision 2.0, and...if it doesn't pan out for you return it and get the Abit. Fry's has the Shuttle AN35N for about $55.00 now too.
if you had the Asus (for example) You would set optimized defaults first, then right away go to intergrated devices and turn off onboard sound and MAC addy, then go to advanced chipset, and first use optimal settings, load your OS and away you go, but if you have PC3200 ram you would need to manaully set the DRAM speed to 166 because you nwat the ram to be in "sync" with your FSB (166/166).
Later if and when you overclock you would raise the FSB slowly and keep the mem in sync at 1:1 ratio @ 100% sync, and raise vcore to about 1.675 - you may need 1.725-1.775 vcore to run at 200/200 (XP3200 levels). Then finally you would be taking advantage of the PC3200 Mem you bought.You would also lock AGP/PCI @ 66/33, and turn off CPU throttle, and fast writes.
An expert overclocker would test with P95, memtest 86, and 3Dmark, CPUz, and SiSoft Sandra beween each raising of the FSB until you get where you want to be. But with the Asus and good ram you could go from 166-176-186-195, then finally 200/200. I run at 235 x 9.5 ..but I have multiplier control because my AMD is unlocked. Yours won't be unless you buy in a tech forum, or E-bay. So you would only be able to OC with your front side bus. but you can still pay about $90.00 for an XP2500 and run it as an XP3200. Be advised though with Value ram your "timings" won't be that tight, and cas latency would only be @ 2.5, but that's ok. Good luck-