Not sure this is the exact answer to the question you're asking, but the only issues I've read about here were slower than expected sortValues() and uniqueValues() functions' performance (now being looked at by FMI development). There was also a possible issue with one of the new Crypt functions not giving the same result as BE (also being looked at by FMI development). I could have missed them, but I haven't read about any show stoppers.
And, others have reported lots of fixed bugs.
I'm getting ready to take the plunge myself...overall, 16 sounds like a solid initial release.
Thank you for your comment, fmpdude. The issues you pointed out will not impact my current development project.
My biggest concern is that I've started the development of my current project in 15 and once I'm done my users may be using the solution in FileMaker 15. So, by upgrading to 16 part way through the development of this solution, will I create problems for myself down the road when I deploy?
I purchase a new version when it comes out. I keep the old version handy. I open a clients files with the version they have and then I cannot add features they don't have!
I suppose some would test for version and branch, but that's a lot of work. Most everyone is at 14 or 15 and will likely upgrade. So I'm ok with my method.
Sent from miPhone
Your users on V 15 will certainly face issues if you create an interface with a Card Window or used the new functions. But I wouldn't expect issues from you taking advantage of the new developer features that you listed.
Best advice will be to test with V15 as you go -- especially after making some grouped objects on a few layouts.
As long as you don't incorporate new FMP16 features you should be fine.
One thing to be aware of, however, is when you do eventually upgrade your users to FMP 16. There are user-facing changes (most prominent being the removal of the bottom window widgets) that some people have taken for granted in their solutions.
Thank you all for your comments and suggestions. Much appreciated.