Our experience with ACS (Optimize) has also been good, but yes you will need to devote time to writing requirements, having a few meetings with ACS, and testing time. But it can be a great way to expand your capacity without having additional staff. They have helped with business process changes, training, workflows, scripts, and other kinds of customizations.
We also had LCS, and that is really only useful if you have someone looking to level up their Netsuite knowledge and/or get their certification. Each class will generally focus on one specific area, and then it is up to the person who took the class to then put the learning into use. It’s more of a long term investment, I wouldn’t expect it to yield as much short-term benefit.