Works well!

Unlike rpapp, I had no trouble running the program after downloading and installing it in OSX 10.8 (Mountan Lion). It does exactly what it says it will do, and the interface is elegant. The ability to change the fonts, sizes and alignment of the address and return address worked just fine (just select the text you want to adjust, then click it, and a popup appears for adjusting the type specifications). Ive also owned various Ambrosia applications for years, including the Easy Envelope widget, and theyve always worked well, and its my experience the developer is responsive through its support access.

Morgan1256 about EasyEnvelopes, v1.0.0