My customer is looking for a Business Process Management (BPM) solution. What they need is simple document routing and an approval system. What are the drivers for implement
I'd take a closer look at the business need that drives your effort (i.e. "business case"). In my understanding BPM/workflow might have one or more of the following goals:
1. Automate actions
This is usually required to replace human with machine through automation of tasks, such as creating documents, archive information, notify users, etc.
2. Tracking of each processes
Companies need to establish tracking when there are a significant number of processes, and business users lose track of them as usually run them in office documents, emails. Every external request for status (e.g. from a client) turns into an investigation.
3. Establish control
For managers it's usually important to gain a high-level view of the process and study it statistically: see whether KPIs are kept to, any lags, exceptions, etc
4. Manage in-process document exchange and collaboration
BPMs often serve as a document exchange tool, as they often enable switch from email and verbal communication to a traceable exchange in a BPM
5. Automate data exchange between enterprise systems
This is a pure integration case and usually is demanded in the case when a number of actions are already performed with (or by) various systems, and there is a need to automate the information exchange among them.
Now, full featured ready-to-use BPMs are good for 2, 3 and sometimes 4. jBPM and other workflow engines are good for 1 and 3, but with an important caveat - they require complex configuration/development.
SOA-based process orchestration engines (sometimes called BPM too!) are good for (5) and (3).
Please feel free to add to the list and argue! I've posted this as my blog post and elaborated a bit more here: http://processmate.net/do-you-need-a-bpm-or-a-workflow/