So, after reading the many insightful replies, I gather it's not really a better or worse situation as much as it comes down to driving style and intended use.
Or fitment issues!
Yes. I'd say the pros and cons come down to intended use, packaging/fittment and production/development costs.
On the first, the advantage of longitudinal torsion bars is spring rate equals wheel rate. Whereas with a coil spring, because its mounted inboard, a higher spring rate must be used to get the same wheel rate. Generally speaking, a softer springing is matched with a less damping which can help suspension follow rougher surfaces.
