PHP > 5.4 only.
As far as I am aware, 5.3 is still the de facto standard, in a lot of hosting enviroments.
That and should you wish to support legacy versions of PHP, it's wise to use the primary methods.
@OP: Great start, work on it more and it could become a handy little guide.
@Lucky: Please stop with the whole "single-quotes is faster", the speed difference, is negligible that it isn't really an issue. Use whatever you wish, whichever you find easiest (or quick in terms of pressing the specific keys on your keyboard).
@Additional (at Lucky): There's only a handful of situations where using print or echo matters over each other. PHP Manual - echo