Looking at a post on http://nathan.crause.name on using RSpec for XML-RPC within Rails, we see another example of why Ruby can suck a fat one. This isn't the first instance I've ever seen of a process just magically stopping under Ruby. No obvious crash, no exception thrown, no results returned. Just ... stops.
So how exactly is this condusive to productivity? Ruby doesn't make you a more productive programmer, it's makes you a luckier programmer if you just happen to make stuff work.
Another gripe I have is "require". It suffers from the same problems that PHP does, namely when you "require" some additional file, if that file also requires some extra files, then the path becomes very context sensitive. This never happens under Java. A package is a package, end of story - it doesn't matter where the actual JAR file is sitting, so long as the JRE can find it, it's available. None of this mucking around with "File.dirname(__FILE__)" garbage.