Some strings work best on some guitars, but not on others. Some plywood guitars prefer brighter strings like Martin Fingerpickers or Dean MArkley Vintage Bronze, whereas some better guitars prefer strings with a less complex sound like vanilla D'Addarios.
But I've yet to hear a guitar that doesn't sound great with Newtones.
Sure, they're not the cheapest strings, and they don't last longest. But they're not that expensive, and they're pretty damn good. I've heard a couple of people report problems with them breaking at the saddle, but I've been using nothing but Newtones for about four years on three steel-string guitars with different bridge constructions (pinless Lowden, "regular" bridge-pinned Crafter and slotted resonator tailpiece) without it ever happening to me.