Hello, we had SCSM in our portfolio as the alternative for CA SDM for the companies that had enterprise subscripttion. In 2013 we discarded it. We had an second project of SCSM and we did some custom workflows, we also made some workflows using authoring tool. Everything was ok on the testing system, but when we went to production after one month random workflows started to fail, notifications was not send auto assignment was not working and etc. Microsoft support performed analysis and made the following conclusions:
"The problem is two folded:
1. Heavy customization of the product which includes large number of custom subscription workflows..
2. The implementation of Relationship changes in SCSM 2010 is causing these workflows do try to do something even on a related item update.
The result is that those workflows are triggered to run too often, which results in large amount of running workflows, which put heavy load on SCSM 2010 workflow engine."
Such performance issues we never had with CA SDM in more than 10 years, and systems are much more customized and even use a lot of customization's that not supported by CA and can not be done with standard CA tools. With CA SDM such situations is simple impossible, You must do something very stupid to degrade it's performance. In CA SDM. if system started after your customization 98% that it will work stable.
At the end just do two google searches: "performance CA SDM", and "Performance SCSM" and you will see for your self.