You really can't go wrong with either one. Obviously Dr. Ron is the OG but Dr. Paul produces results that are just as impressive. I get the sense that Dr. Ron may be a wee bit more conservative than Dr. Paul. Also I think that Paul employs the use of aggressive micro irregularities, even more so than Ron, in his hairlines to produce natural looking results. Both are elite, artistic, and highly committed to their craft.
When looking at their results, it is hard to tell the difference between the two. Good luck!!
Call Jana or Matt and they'll give you their inputs on their differences.