Pros
Segundamano.mx is a great place to work, everyone is very friendly and the office culture is great! They pay good salaries with good amount of benefits and vacations. Also the main offices are on Europe (yes, it is NOT a Mexican company) so there is a good chance that the company sends you overseas to train or to help other teams. The company is very "international" and you got the chance of interacting with many different nationalities and cultures. The amount of work is reasonable.
Cons
Worst code-base I've ever seen in my entire life. You will have a hard time (I mean, a REALLY hard time) developing for them and learning their "home-made" technologies. They use old technologies with no Software Engineering at all, and there is no possibility to change this (believe me, many had tried). If you are not a mobile developer, you will NOT use a "formal language" to develop (like c#, java, c++, php, python, js), so any expertise you got inside that company, will only be useful inside it.