I generally choose Grails (although the move to 3 is going to be a bit bumpy without all the plugins from the 2 field).
The primary deficiency I've found is startup time - when I move to other systems, I remember - oh yeah, projects can start up immediately, or in < 3 seconds, not 50. I know 3 is better in this regard, and I'm looking to migrate one project to it next month.
Grails never got the mindshare because it was jumping in to a full ecosystem. Rails, by comparison, was essentially the only game in town if you wanted to do Ruby - there weren't any other major competing frameworks.
The other big strike against Grails is... "it's different!". Most shops that are large enough to see big benefit from Grails and similar frameworks also tend to be rather stodgy and slow to change (perhaps with good reasons, but slow anyway). The sort of people who champion 'new' tech largely migrated away to completely other ecosystems (rails, node, etc). Grails/Groovy are 'different' in a scary way for "slow to change" shops, and "not different enough" for the folks who are always looking for "new/shiny" stuff to dig in to and promote. It was/is too "middle of the road", I think, to benefit from the advocacy often required for adoption. And in a crowded JVM-tech field, that hurts.
That said, it's still a great stack, and I still recommend it for many situations.