The first strategy is recommended as a temporary one. It is intended for users who have OPM applications and who, perhaps due to lack of time, cannot move their applications to ILE all at once. The second strategy can also be a temporary one. It allows you time to learn more about ILE, but also allows you to immediately use some of its features. The third strategy is more involved, but offers the most flexibility.
Both the first and second strategy make use of the one-step program creation process, namely, CRTBNDRPG. The third strategy uses the two-step program creation process, namely, CRTRPGMOD followed by CRTPGM.