My background: FTE and direct employee with US education and this was my 4th extesnion.
Mexican visa: I got one because my H1B visa had expired. Please see this link for visa requirements:
https://consulmex2.sre.gob.mx/washington/index.php/visas?id=182
The visa appointment process and getting the visa was easy. You can also get a 7 day permit at the border.
Agent: I picked Mr.Salvador as my agent and he is also the general manager of the Best Western in Matamoros. His services are excellent! He or his staff will pick and drop you off for all the visa related requirements. He is a humble 72 year old man with good knowledge of Matamoros and the Visa process but he will avoid answering any legal questions.
https://mexicovisaservice.appspot.com/. The Whatsapp group on the webpage is helpful.
Visa fees: After you fill out the DS-160 you can ask Mr.Salvador to pay the fees. I sent him money via MoneyGram and then after he paid the fees I got a confirmation number. This number you would then use to book your slots for ASC (fingerprints) and interview.
https://ais.usvisa-info.com/en-mx/niv
Timeline: Second week in December.
Day 1: Arrived at Brownsville airport. I took a cab to the Greyhound bus station where Mr. Salvador was waiting for me and he drove me across the border to Matamoros. There are no delays when driving across the border and they don't check your passport or visa. It's good to have a visa or travel permit because the hotel can get audited or you could stopped by the Mexican military or police in Matamoros who may want to see your papers.
Day 2: Along with other applicants I was dropped for fingerprinting at the ASC center in the morning. For H1Bs you only need DS 160, I797 and passport.
Day 3: Interview. This was a quick an easy process for me. I heard that others were asked for letters and W2 forms but the day I went everyone's visas was approved. I was asked to come the next day to collect my passport. There were some who got it at the same day at 3pm.
Day 4: Collected passport at 1pm. Got dropped at the border crossing. Be prepared to spend at least 60 minutes here ( times vary) and you will be asked questions by CBP officials before you are given a new I94. I then walked over to the US side and took an Uber to the Brownsville airport.
I had a very good experience and would definitely recommend the services of Senor Salvador. Good luck to all of you!
Tips:
1) Have exact change of $6 for I-94
2) Carry 4 quarters for the turnstile to enter the CBP office. There is a change machine there too.
3) You don't need Mexican pesos or dollars but do carry a good amount of 1 and 5 US dollar denomination bills.
4) Do meet up with other applicants at the hotel. All are in the same boat and people are helpful.
5) Book only one way flights or give yourself a few more days just in case there is a delay.
6) The US State department has issued a travel warning for visitors to Matamoros. Avoid travelling out late at night and always check with the Best Western hotel staff who are extremely helpful.