I am sure there are many types of African djembe styles and techniques, depending on the locale you're in. Same for conga - techniques can vary with the type of music, the location, even with the individual.
That's a really interesting point. I've got questions in my mind now! How does Cuban technique vary from 'Western' conga technique? Are there differences between Latin technique and say funk/R&B technique, or between, say New York players, and west coast American players? And so on.
In terms of Latin v other styles, to generalise I think R&B percussionists tend to use less of the great variety of strokes that are available - e.g. different types of muffled tone - heel-toe in particular. Perhaps because many are multi-percussionists who don't have the luxury of being able to work and practice with the conga drum to the extent that the 'conguero' can. Nonetheless many are great players in their own right, but perhaps approach it more in a Brazilian fashion - which is transferrable to different hand-drums.
What does this amount to? I think you need to get down with Latin music in order to get the most out of the drum!
Simon B