I’ve heard nothing about Sim struggling. They came out with the North line which appears to be doing well. Many dealers - lots of support. Great warranty, reliable build quality It seems to me that they’re more likely to be around longer than the vast majority of companies.
Yes - tariffs are and poor economic policy that willl hurt all consumers universally (I’m a finance/economics person) by triggering price inflation. That will spill through for domestically manufactured (assembled) products.
I heard the 390 several years ago and came away thinking it very nice and functional for the price. Fairly detailed - a touch bright at output. Their software is different but competitive. There are others to consider that will offer a different flavor, but I think most would be pleased with the price/performance.