An excellent comparison of the difference between a Mexican and US Notary can be found here
David Shafer August 27, 2005
General Information on Notarios
David Bodwell - 06 Dec 2003
A Mexican Notario is NOT the same as a Notary Public although he can, as a small sideline to his regular business, notarize signatures on contracts, etc. A Mexican Notario is a fully licensed lawyer (abogado) with at least 3 additional years of training before he can be licensed by the State as a Notario. He is the person in Mexico who plays the same role as a Title Company in the US. When you want to buy property in Mexico (via a fideicomiso - bank trust - if you are less than 50 kilometers of the coastline or 100 kilometers from an international border) you hire a Notario. The Notario you use is YOUR choice, it's advisable NOT to use the seller's Notario or a Notario recommended by the seller or his agent (there have been clear-cut cases of collusion in Mexico - a mess in Baja Califoria is the latest). Get recommendations from others. He checks out the title (a title search) making certain that it is free and clear of all liens and encumbrances and that the seller has the right to sell it (important in Mexico). He draws up the purchase contract (which is the title) or if necessary, a fideicomiso. When everything is in order you and the seller meet in his office and he witnesses the signatures then tells you that you can now pay the seller. My Notario only accepted me as a client when I agreed that I wouldn't pay any money to anyone except in his office with his approval. He then files the papers with the city, state and in the case of a fideicomiso, with the federal government.
Since he is a lawyer he has also handled small details for me such as my Mexican will, etc. NOTE: If you need US or Canadian documents notarized it is prudent to do this at the US Consular Agency or the Canadian Consulate as a Mexican notarization MIGHT not be recognized. If you need legal copies of documents in Mexico you make a copy (or copies) take the copy AND the original to a Notario and he will notarize the copy as a true copy of the original which then can be legally accepted as an original.
Roger Culbertson - 25 Mar 2003
Most foreigners do not realize the importance and power of a Notario Publico here. Many feel they need a Notario AND an attorney. You do not. A Notario is an attorney. He works for you. He looks after your interests. His word is law if there is a problem. That is why it is critical to have a good one. There are at least 25 Notarios in Mazatlan. We use two. That is because they have a sterling reputation, and a track record with us. NEVER, NEVER, NEVER use the seller brother in law, or the listing brokers cousin. They may be just fine, but that may be just a little to cozy. I have seen many disasters here. Ask around and get recommendations.