After a short stint in Windows, made easier by AutoHotKey text expansion, I am firmly back in the land of Mac. I naturally jumped in to TextExpander but at $34.95 it was a struggle to justify it long term for lightweight text-expansion-only use.
So I hit the App Store.
After a brief stint with "Smart Typer" (subsequently refunded by Apple due to it being grossly incapable and buggy, I found aText.
aText accelerates your typing by replacing abbreviations with frequently used phrases you define.
It works perfectly, all for the modestly affordable price tag of $5. You can save yourself a lot of trial and error if you're looking for straightforward OS X text expansion and go straight to aText.