I’ve had Shure SM mics in the past, and they are indeed very robust.
I have to say that I think the Shure PG range is very underrated. My current vocal mic is a PG58 and I use a PG81 for the mandolin. Either one works for whistle too with my Marshall acoustic combo (or straight into the PA) - but if I use the condenser it needs to be further away than the vocal mic to get a nice tone.
The PG series is as tough and heavy as the SMs and, to my ears, very close in sound quality. For quality recording you might notice a difference, but for gigging they do a grand job at a good price.