I've been thinking what would be the best and most faithful gaming experience for PS1 or PSX on PS Vita. It is better to use the Core PCSX Rearmed in Retroarch or or it would be better to use Adrenaline.

Is it possible to do that?The most accurate way is not available yet - it would consist of an hypothetical "NoPspEmuDrm" plugin to allow displaying and running PSP/PS1 eboots directly from the Vita home screen, with no interference from custom gimmicks and allowing full integration with the system (Content Manager, Pocketstation emulation, ...)
"Possible" yes, "has it been done" is another question and for now is noIs it possible to do that?