ive used both HY150 and RE500 and my pref is RE500 for more practical reasons.
*HY150 dries white and therefore is more visible (500 is dark red)
*HY150 sets very quickly. we had some dry in the nozzle after less than a minute making a big explosion of glue when we pumped the gun.
*RE500 looks cooler.
*yes RE500 is more expensive but if you know the right people then, well….
*RE500 and HY150 nozzles are not interchangeable so choose what ur going to use and stick with it.