Sorry, but... Zoneminder *is* the state of the art in Linux DVR software.
And for reference, having recently compared many different versions on different operating systems for a project at my company, Zoneminder IS the state of the art in all platforms of DVR software. It's one of the only systems that will work with many varieties of end-point hardware cleanly. Most dedicated embedded systems will only work with their brand of camera, or a single video protocol.
There are systems that will link motion sensors and contact alarms (Zoneminder can do that, too, though it takes some finangling). Again, most of these only work with *their* hardware.
The biggest things to keep in mind are bandwidth, storage consumption, and retention. A camera input card may have a very large 'potential framerate', but when you spread that among the 16 inputs you have coming in, things start to add up *very* rapidly. There are physical limitations on the hardware that you will run into if your deployment is of any large size. Our deployment is one of the largest, having 80 cameras currently (planning on adding another 16 before too long), and we have to spread the load out among 5 high-powered servers with relatively large amounts of RAM. Even with that, we still need to upgrade our switch infrastructure to gigabit in order to be able to view all the cameras simultaneously! We've got fiber to our SANs, though, so storage and later retrieval of footage is no issue.
The only downside is the lack of professional support - Management doesn't have anyone externally that they can point at if something breaks.
If you're a power Linux user, I'd recommend Zoneminder. If you have a few cameras for a small business and are not technically skilled, I'd recommend a pre-packaged solution - but expect to spend more for a similar sized installation. If you have a LOT of cameras (more than about 16) but are not technically skilled... I'd recommend finding a consultant who can deploy Zoneminder and contract long-term support with them.