Low pay and poor benefits. Low 401k matching. Most kids out of college don't know what "good benefits" are. Esri hires a lot of recent graduates to keep up with their high turnover. At Esri, you'll notice a trend in employees. Usually you're either (A) a veteran who has been there forever or (B) a relatively new hire with less than 4 years at the company. Coincidentally, after 4 years your 401k is vested. I suspect that employees get "pushed out" just before that time and then replaced by a recent college graduate.
HR. Don't even get me started. An event occurred a few years ago when the markets went sour. Esri hired new HR management to "make things more efficient". Instead being upfront and laying people off, they began finding extremely petty reasons to cite people for rule violations. Internet usage, phone usage, dress code, rules that nobody knew existed, etc. The result was that a lot of people got fired or were forced to resign. This event set a tone for how HR works at the company and has persisted until today. Backstabbing occurs at Esri when someone finds a way to build a case against you with HR, who will undoubtedly make your working life hellish. For example, you may be forced to attend an hour-long meeting with HR every other Monday to do performance reviews for the duration of 6-8 months. In these meetings, they will have all of your email correspondence printed and will review it with you, looking for ways to take your written word out of context and perpetuate their case against you. During this time your manager will tell you that HR has blocked your annual raise.
They advertise a "flat management style" as a benefit. This is Esri's way of saying "once you're hired we won't pay you more money for position moves later in your career". Esri's biggest expense are salaries for their employees. They will fight you tooth and nail to keep your salary as low as possible. In actuality, the flat management style is just a myth. Esri is riddled with all different layers of management and bureaucracies once you cut through the smoke.
The company isn't doing anything new anymore. Nothing revolutionary has happened since ArcView 3.x and they're still milking the GIS desktop cow. Esri server software and enterprise solutions are just bandwagon products that they had to create to remain relevant. The lack of recent product innovation has led to a penny-pinching culture where someone's cost-cutting initiatives are more valuable than innovative product engineering that should be taking place instead.