I've flown with Zero Hallibuton bags for a very long time, many times going through all the TSA misery. Of recent years I kept them unlocked.

What put me off using them was their weight empty. I can't manage so much weight any more.

I have carried various sorts of equipment in those checked bags and all survived without being stolen. However, (and weirdly) I have had underwear stolen from my checked luggage on several trips.

If you lock the bag and the TSA breaks the lock, they are relatively easy to replace. Check with the maker to find out if they will sell you locks.

When the bags start looking nasty, you can clean them up with Bon Ami cleanser. Yes, it works well.