Pros
Solid team - The primary thing that got me and my colleagues going at ZL was the team we worked with. Despite management trying its best to suppress friendship and bonding, we shared information freely among one another, and never threw anyone under the bus. The ZL products themselves are of high quality, led by a gifted CTO and development team. If you can grab onto a key project and own it, you will be able to grow with it very fast. This is where a "start-up mode" works to your advantage - you can manage projects from ground up to finish.
Cons
Minimal potential for growth - Unfortunately, management tends to tell potential new hires that "1 year at ZL is worth 3 years in the 'real world', and that working in a big company is a waste because you are pigeon-holed and won't get to do anything of value". While this might be true in a start-up that empowers its employees, unfortunately, it does not at ZL. Employees are typically given tasks in pieces that may or may not be used, and feedback from management that has no real management experience is ultimately useless. There are no annual reviews, or performance feedback meetings, unless you request them, and then they are usually a meeting of "what you did wrong". Constantly harassed - ZL used to hire only immigrants with "visa issues". It was clear that the management felt that they were most likely to stay longer, and tolerate more from management. If management did not like someone for any reason, rather than address the matter privately, they publicly humiliate the employee and reduce his/her importance in the company by changing a title, or taking away projects. Mom-and-pop environment - ZL is essentially run by a CEO and his wife (admin/HR/accounting). There is zero accountability and if you have a problem with anything - there is not much you can do about you. Also they nickle-and-dime employees in every way - from benefits to expense reports. The management also fosters unhealthy competition and backstabbing, which he views as "natural aggression" amongst "high-flyers". High turnover - ZL has been recruiting from different schools over the past few years - usually going after one school, building up a bad reputation, and then moving on to another. New hires quickly report back to the admissions or recruiting teams at their alumni, making it near to impossible for the company to continue recruiting at the same place year-after-year. People with visa issues aside, most new hires make the decision to leave within 3-6 months.