When creating a poster in Photoshop with 300 dpi settings and export to high res PDF, text do not look crisp enough (after rasterizing text objects). Will it look good after print? Or should text objects remain not rasterized?
It is traditionally best to not rasterize text if it can be avoided. If you save a PDF for high quality print output using Photoshop and don't rasterize the text, it will be embedded within the PDF and print using vectors and type hinting. Type hinting can be crucial for small text (below 12pts). There's little reason to rasterize text for output in most cases.
As for whether something "will look good after printing" -- There's no way for anyone here to know. We can't see your artwork.