It can be learned by a programmer knowing only imperative C-family languages in a couple of hours, meaning I can hire any average developer and make him productive in less than a week. Not the same as teaching pure functional style with pattern-matching and prolog's syntax. Go is also much more efficient. It also produces static executables and can be easier to deploy -- or not, depending on the exact situation. It handles strings nicely -- anything other than Erlang's approach to strings is nice.
Erlang has other advantages, though. 99.9999999% uptime and hot code replacement are easier with it, for instance. Their ideal niches don't completely overlap.
I don't know much about Factor, it's a Forth implementation right? Just inspired by Forth?
Either way, the example[0] I was greeted with on the homepage[1] is quite awesome. Does it have an actor implementation like Erlang? How does it handle concurrency?
0:
USING: io kernel sequences
http.client xml xml.data xml.traversal ;
"http://factorcode.org" http-get nip string>xml
"a" deep-tags-named
[ "href" attr ] map
[ print ] each
Erlang has other advantages, though. 99.9999999% uptime and hot code replacement are easier with it, for instance. Their ideal niches don't completely overlap.