I went to the Mexican consulate in Houston for the first time about a week ago. Got the matricula for $27 and during the process my mother suggested renewing my expired passport, paid $101 for six years. I arrived there at 1.30 and left at 6.45. The place was crowded, the employees and everyone in general were very friendly. As long as you provide all the required documentation and make copies beforehand the process goes really smooth. Bring a companion, a book, or music. I like showing my matricula better than showing my tourist visa's copy.