If you like the JD i would say move it to the 150. It will be much happier in there. There is room for a potential breeding partner and/or tankmates as well.
I find that JDs do best as the dominant species, so i would stay away from other larger or aggressive cichlids. For tankmates consider medium sized dither fish like mollies, denison or spanner barbs, or giant danios. For bottom dwellers consider hoplo cats or maybe even smaller bichirs.
Keep us posted with your progress.