I've been running some benchmarks against Seaside on Dolphin.
I must say it runs very well, with an good page/sec rate for business apps. Anyway it can't handle being "slashdotted".
However, there is a severe problem with something leaving dangling processes in suspended or dead state, which collapses the image after 4 minutes of brute requests (above 8000 requests one after the other), generating a similar number of processes (think of it, 8000 processes!!!!).
Something smells near the Continuation implementation. Once solved the request rate should rise.
I'll publish the graphs and results when I learn how to do it. :-)
Even with that "little" problem, the performance is a little better than the Squeak implementation (15% faster).
More coming soon...