Addams is one of those perfect integrations of design and theme. There's a reason it sold so many units. Great game.
TSPP was built in a time before cost-cutting gutted the BOM for Stern. This game has WAY, WAY, WAY more to do and IMO is much more engaging. Keith created the perfect code package for a design that is very similar to Addams. Great game.
Addams would probably be harder to replace and will likely outstretch Simps on price down the road.
IMO Simps is much more fun.
I had both and was forced to sell both. If I could get either one back today I would get Simps.