Right now, that's truer than many would like. However, when GHC 8 (the new version of the compiler) drops in the next couple months, most of the performance tuning will involve putting a single line of code at the top of each performance-critical file. That line will make all evaluation within the file strict instead of lazy.
A lot of the performance and predictability problems in Haskell come from its laziness, so the ability to toggle that on and off on a per-module (read: per-file) basis will be a game changer.
That does sound significant. I will be curious to hear more about that. Can you recommend a good go-to resource for all the latest news and discussions on Haskell?
Mostly I just read various people's blog posts and follow links (for example, I think I first found Stack on [1]). I also spend occasional time in the IRC, which can be useful but isn't a comprehensive news source by any means.
I hear some of the mailings lists are informative - iirc there's a haskell-beginners one which will probably cover major updates in tooling, feature releases, and so on. Good luck!
A lot of the performance and predictability problems in Haskell come from its laziness, so the ability to toggle that on and off on a per-module (read: per-file) basis will be a game changer.