There are many open source and "small" software companies that provide OGC web services. I get asked a lot of questions about how our product "measures up" against many of them. 100% of the time, none of the open source or small software company offerings meet the requirements of the prospective client or provide a level of confidence that they will ever provide the capability.
Open source offerings are mainly pitched by services companies. These projects provide a lot of "opportunity" for services companies because they require so much customization to meet client needs. This customization provides the opportunity to become "locked in" long term to continue to provide "features" for clients. It's interesting how many service companies are also "technical advisors" for many government agencies, even very large ones.
Small software companies have "niche" market technologies. For instance, they provide web service layers on top of spatial feature database storage. I see success with feature editing through WFS-T for some small organizations. They usually have a very "narrow" feature set, but a market differentiating capability. Most are looking to be "gobbled" up (bought).
The problem for most open source or small company offerings is the inability to provide confidence or the ability to commit to the capablility of supporting the scale of implementations of large customers. They also fail to provide the support required of large production companies, the ability to commit to them.
All of the offerings fail to handle the quantity of data and the load required for large organizations in a production environment. They are currently filling "small" organization requirements, or are in large organizations at a small scale. Step up to 500TB and 1500 concurrent users!
For the Leica Image Manager, it's relatively easy to differentiate ourselves in that Leica is the market leader in imagery. There is no question that we dominate the imagery market, provide end to end imagery production and dissemination systems in large scale production environments. We write and manage gridded data accessors (we don't rely on open source for our imagery support or another company). We handle any type of gridded data that you may have (over 160 image formats supported by Leica software), any sensor model and any workflow. We have great BRAND EQUITY. This means a lot to an enterprise when they are going to invest into software. They trust that you have the capabilities to handle thier data, the quantity of data that they need to handle and the support that they will need. They also are confident that next year, the product will still be around, being improved with new features and be on the forefront of handling new sensors, formats and technologies that are occuring in the market. Never underestimate the power of the brand.