With that being said, the Blade 150 does have a few things going for it, and it makes a great little web server. Here are the pros/cons as I see them:
- very low power consumption. My 650MHz pulled 42W at full load, and went down to 26W after idling for a while. A Blade 1000, by comparison, pulls 210W (single proc) or 280W (dual proc).
- very compact, and only weighs 35lb. Blade 1000 weighs over twice as much.
- reasonably good case design, so it's easy to upgrade/mod compared to the Ultra 10
- very quiet, but the Blade 1000 is also quiet (if you have Solaris installed)
- has USB and an onboard framebuffer
- it's slow. Solaris 10 + JDS (Gnome) run, but not very well. It's much better suited to running S10 headless
- only takes up to 2GB memory (bad for Solaris 10+ZFS), and it takes unregistered ECC RAM which is harder to come by than fully buffered, ECC
- ATA/66 (I think) controller is slow (faster than the Ultra 10 by a lot), and it can only address 128GB of space per disk. If you are feeling adventurous, you can buy ATA/100 controllers that are Solaris compatible, but they aren't bootable.
- its peripheral PCI bus is 32-bit, 33MHz which means you really can't upgrade storage controllers. Various Ultra3 and FC HBAs are compatible, but the underlying system architecture is just not designed for high throughput
I guess what it boils down to is remembering that the Blade 100 and 150 were cheap machines. I think there was a time when Sun priced them at sub-$1000, and people got what they paid for. They're now 7-10 year old machines, so I think paying over $100 for one is really not worth it.
That being said, I just paid $50 for a 375MHz RS/6000 43p, so it might be worth it to you.