Pros
The owner of the company was extremely loyal to his employees. The company had the feel of a small family-run business.
Chopper had a significant presence in the several markets prior to its acquisition by DRW. Chopper was in some trades that required a tremendous investment in infrastructure that a small company was not able to handle. However, the caliber to the traders, software developers, and network engineers was top notch.
The interview process was extensive and the bar was set high.
Cons
They were a little over-aggressive with security policies. The development environment was air-gapped from the internet, which made some types of work difficult. This probably also led to less open-source adoption and incorporation of best practices from the industry. There were certain internal, auxiliary projects where it would have been better to allocate resource differently.