We put a standing seam roof on our place 18 years ago, zero issues so far and I we get fine cell reception. It has been a good value for us, came with an “80 year” warranty, whatever that means. I’d imagine if you’re in an area with marginal reception, the roof would force you outside. The only negative I could see is the noise with a hard rain or any hail.
I think the cost of steel went back down, not sure, you’d probably need to check on pricing. We had the installers that did the houses @ the Jackson Meadows development outside Marine on St. Croix, so they were pretty experienced when they did our place.