This is pretty much identical to a 9800GTX+.
At $35, it’s worth it even if it gathers dust on your shelf as a backup card. It’d also be decent (though overkill) as a display-only card.
You could arguably make some nice Folding@Home boxes with a bunch of these, too.
One thing to note is that the 9800GTX+ and the GTS250 seem to have really highly clocked CUDA cores. So not only are you getting 128 cores but they’re clocked at 1836MHz vs. a typical 1340MHz – a 37% increase.
Also note that the GTS250 supports “Compute Capability” 1.1.
Awesome - now my new system has a name! (I’ll have to give you an account.) Except that it won’t be the hamster cluster, it will be the hamster SUPERCOMPUTER!