[1] https://github.com/Gabriel439/post-rfc/blob/master/sotu.md#d...
If the current state of Distributed Programming in Haskell is "Immature", then I can't wait to see "Mature" :)
http://stackoverflow.com/questions/25280852/space-leak-in-pi...
It's often better to just include the writer part you need in a larder State type (lenses make this really seamless)/
It seems to be a matter of laziness. If you're writing some small piece of state like an Int, this can be a real problem. If you're writing out a lazy data structure like a list (as happens in the article), I think the extra laziness should be fine or even desired. (I've never used Writer in practice, so take my comments with a grain of salt!)
[1]: http://comments.gmane.org/gmane.comp.lang.haskell.libraries/...
AFAIR the problem with WriterT was the use of mappend within is always lazy, regardless of the strictness of the w in WriterT w m a.
Probably my most significant previous use was in my second-semester computer architecture class as a substitute for Verilog. Using Christiaan Baaij's Cλash project, one can transform a (large) subset of Haskell into VHDL/Verilog/SystemVerilog and slap it on an FPGA. There's a rundown of that project on my blog too.
My project partner had never really used Haskell before, so he was learning as we went. By the end of the semester he was writing code no problem. "Immersion learning" seemed to work quite well here.