The real question for me is which direction offers the best performance, that was 50% of the reason I bought NGUI in the first place.
If there is better performance and the difference is enough to justify the work to migrate then it's worth it.
For any new projects being created, it's worth it.
If the difference isn't large, but there is some advantage beyond the ease of migration, it's worth it, IF there is a substantial discount for existing licensee's.