Just got this a few weeks ago. I wanted to build a custom startup utility with more than just TechTool Pro (Diskwarrior and iDefrag to name a few). Worked quite well on a small external 5 gig FireWire drive. No issues booting an Intel iMac or PPC Powerbook. Then tried using an 8 gig USB Thumbdrive. That works too but boot time is pretty slow. And I should point out you can ONLY boot an Intel Mac with a USB thumbdrive (not PPC). Still, this is a useful package. Rather than booting from say the agonizingly slow Diskwarrior CD, this is a much faster process, plus you can run multiple utilities on the boot disk. So its nice to defrag, then run Diskwarior and maybe Techtool if you want.

For on the road, this should be a very useful product once you build the disk as you wish. Not inexpensive but so far, I'm happy with the product.