My first comment is that I would not take the word of the US Embassy over any DR1 member who lives in the DR and has 1000 or more posts. (and if you want, go ahead and discount my opinion too, even with 1081 posts). Ever, in ANY situation.
The embassy/consular people turn over every 3 years, and it takes at least that long in the DR to get your bearings and your feet on the ground. Collective government wisdom normally consists of GIGO. They also have their own collective agendas. Most longterm DR1ers don't have an agenda other than maybe being a bit rough on newbies or sockpuppets.
The attorney who did my residency work specialized in residency and really, REALLY knew her stuff, as well as knowing every single person in every single office that dealt in the residency process, and many DR1 people used her services for residency. Unfortunately, she has apparently given this work up for politics. I'm sorry, but I cannot personally recommend anyone else for this type of work.
I have used Biaggi & Messina, located on Ave Abraham Lincoln in La Julia in Santo Domingo, directly across the street from Vimenca's main offices, for general business law, and other minor matters. They know their stuff, they are "plugged in", and they get it done. Correctly. They also do international law, business incorporations, family law, wills, etc.
I have had dealings with a couple of other firms mentioned in the report you included, but walked away when they chose to act in ways that I did not appreciate. Others may have had better experiences with them, or higher tolerance levels than I did. I dealt with a few young attorneys who would have been doing minor work for me, but if they want to be treated as professionals, they better act as professionals....and if they are reading this, they know who they are, and the circumstances. Perhaps they need better, or closer, guidance from the senior members of their firms. And trust me, they DEFINITELY knew that I was not pleased with them before I left....
If I am paying the bills, they work for me and do the work I am asking for, or else I leave and find someone who will do so. I have never been shy about letting them know upfront what I expect, and in return don't try to negotiate their fees. I expect that they know their value, and can set their fees based on my expectations. Biaggi & Messina were more than happy to accomodate me, their fees weren't cheap, but they got it done to my satisfaction.
I have also met or associated with a few of the other attorneys from firms on the Embassy list who wear very expensive suits, knew all of the right people, know all about the finest wines and restaurants, wore expensive jewelry, had extensive government contacts (or partners serving as members of the Dominican government), but underneath it all, they "felt" too slick. In my travels, I have run across some of their work for DR citizens and/or businesses in other countries, and a lot of their work which I have seen outside of the DR has been slimy.
Good luck.