It's used a lot for things like analyzing clinical trials, e.g making futility or early stopping calls in interims, or for meta analysis. JAGS may still be the

It's used a lot for things like analyzing clinical trials, e.g making futility or early stopping calls in interims, or for meta analysis. JAGS may still be the most popular, at least in some companies, but Stan is starting to catch on thanks to its greater flexibility in most respects.