A few pros of maintaining an in-house product catalog system are better customization and the ability to implement new features at a faster pace. If you have the required manpower, an in-house system also enables you narrow down and solve problems faster. With proper planning, it might also have a lower lifetime cost compared to off the shelf options.
Some cons of an in-house catalog management system are the lack of specialized support, potential for downtime, and the potential for bugs. If you are bot a very large operation, an in-house system will be a significant drain on your resources. The time needed to create and bring an inhouse system online is also very significantly longer.