In my humble opinion. Yes. Experience and a solid track record of good support is essential. But just my take on it, don't shoot me WMS vendors :-)

I think Paul's answer is a great outline for what to do! The only thing I would add is making sure you require a WMS vs. a WCS (Warehouse Control Software) system. It all depends on your requirements, budget and implantation time. Both are good solutions... for the right set of requirements!

Choosing a Warehouse Management System
By Deborah Catalano Ruriani source www.inboundlogistics.com

Purchasing a new Warehouse Management System (WMS) for your company is a little more complicated than simply interviewing a group of companies and picking the most newfangled or expensive product on the market. You have to know what drives your company and be able to weed through all the bells and whistles to target your specific needs and select the solution that best matches your business objectives. Mark Swenson, vice president of Jacksonville, Fla.-based TMSi, a third-party logistics provider, offers these 10 tips for selecting your WMS.

1. Operations experience is a plus. Seek out providers that combine operations experience with state-of-the-art Warehouse Management Systems. Many contract warehousing providers have developed excellent systems with real-life operational know-how. These businesses are capable of adding critical input from their organization's top operations people during the development and ongoing enhancement of their WMS. The result is a very practical system that is tried and proven and will likely gain quick acceptance from employees on the floor.

2. Conduct a business needs assessment. Before you go through the process of selecting a WMS, you must match business requirements to functionality. It is very difficult to choose an optimal WMS without first identifying your company's key business requirements.

3. Ability to interface is critical. Ensure that the WMS has open architecture and is able to interface with your ERP system without incurring excessive costs. Ask prospective WMS providers for case studies where they have previously interfaced with your organization's specific ERP or accounting system.

4. Control modification costs. Choose a WMS provider that has reasonable modification rates and is willing to set up a realistic budget, based on your needs assessment, prior to formalizing the relationship. You can also modify costs by choosing a provider that has already installed WMS systems with clients in your industry. In such cases, the base code of the provider's WMS may already reflect the industry-specific modifications you require.

5. Support during installation is crucial. Make sure that the WMS provider can support you during the implementation phase. Prior to making a final selection, ask the WMS provider to share a detailed implementation plan that includes an installation timeline and resource commitment.

6. Help desk support is key. Select a vendor that has a responsive Help Desk and enough resources to provide ongoing support at a previously agreed upon rate. Help Desks play an integral role in reinforcing user training, troubleshooting problems, and supporting system upgrades. Partner with a WMS provider that has an adequately staffed Help Desk. The Help Desk should work during your company's hours of operation.

7. Keep it simple. Look for a WMS that provides adequate functionality to meet your specific business needs. Do not simply purchase the most sophisticated WMS. This invariably leads to longer training cycles and poor return on investment.

8. Select a WMS that is user friendly. Focus on Graphical User Interface (GUI) systems that employ 100-percent point-and-click operating environments. These types of systems have a positive impact on operator productivity and satisfaction ratings.

9. Guard against future obsolescence. There are two key points here: First, verify the WMS is scalable in order to accommodate future sales growth and/or acquisitions. Second, ensure that the WMS is adaptable to the next generation of technology including voice recognition and/or RFID technologies. Verify that your prospective WMS provider is reinvesting significant capital into research and development, and future product enhancements.

10. Make data accessibility easy. Look for a WMS that allows for easy data retrieval. For example, ease of conducting inventory queries, cost-to-serve modeling, and performance reporting are key elements in choosing the right WMS.

It doesnt matter if the company is start up or well established, you need to do thorough analysis and put forward your requirements in front of the supplier,he will surely come up with some strategy or solution. You need to see whether this solutions align with your operational needs, if yes..then the rest of the things like contracts, maintenance can be managed..

A WMS is not something that you can just build, you need operational expertise. A good WMS is one that has been built up over many years with the assistance and input of many different industries.
Also good references are a must.

Mark Clinch
Business Development Manager
Paperless Warehousing