Regarding your troubles with "ordering of operations". I've found it varies on installation, but that each team works to avoid these issues by setting a standard on module development. So that when you "include 'ntp'" you know exactly what you are getting. I've seen many different ideas on how to accomplish this, all of which made it really easy to include without ramifications.
Also, regarding testing. I think this is an issue with both Chef and Puppet. Something I hope someone addresses at some point in the future. I've seen some custom tools with some promise (Chef focused) but perhaps a Vagrant setup might be the best answer these days.
I'll write up more about Chef later, but I really look at the two differently. Puppet is really great at managing infrastructure and server state. Chef is really good at integrating with your application (especially if you are using Ruby). I typically think of Chef as a framework to program your infrastructure against. Puppet is more of the middle manager. :)
Both are easy to test, with Puppet winning slightly with 'puppet apply <manifest>'. Chef-solo is nice but takes a little bit more to setup (solo.rb and node.json for example). Either way, test and see what you think will work best for you.
Also, regarding testing. I think this is an issue with both Chef and Puppet. Something I hope someone addresses at some point in the future. I've seen some custom tools with some promise (Chef focused) but perhaps a Vagrant setup might be the best answer these days.