Using Linux as an OS on any system allows for several advantages:1. Open source code: You can review and modify to your company's specifications. You can not do this with almost every other OS.
2. Open source drivers: You can create your own or use those from the industry.
3. Open source is supported by many more people and vendors because of its availability. Therefore, it's easy to get working software for a reduced price.
4. Price tag: Very low cost.
5. Security: Many security threats are already resolved, because people have looked at the code. The opposite example is Microsoft. Their biggest problem is that no one outside the company has been allowed to review the code.
As for PAM, beta doesn't mean the same as in the Microsoft world. Linux beta in most cases means the product is almost ready to go and is being tested. PAM provides so much flexibility that I would recommend testing it first before installation. Because it is so new, I would recommend applying patches as soon as they are released.
Here is some extra info to help you out with PAM:
For more info on this topic, check out these SearchSecurity.com resources:
This was first published in November 2003