Strangely enough I've just had the opportunity to evaluate a fortinet device (can't remember the exact model as its at the office) and I was quite impressed with the overall performance and security options.
To put things in the correct prospective, I don't really like 'all-in-one-box' devices as the majority of these devices belong to, but I can see where they can actually come in hand and give some pretty good results.
If your looking for a somewhat cheap solution to protect your network, then these devices can do the job for you.
More specifically, Fortinet's firewall device can act as a firewall, proxy, anti-virus, IDS, IPS and much more. The vendor offers online subscriptions which allow the device to automatically retrieve the new updates of its operating system.
The user interface is simple and impressive, performing a good job of keeping the user from being confused and overwhelmed with the available options.
After working with the product for around 2 weeks, I have concluded that it's a good choice for a small to medium environment with not more than 30 people and want to keep the budget as low as possible.
Anything larger than that means (in most cases) that your network services are also more complex and one box can't simply cover you 100%. For these scenarios, I'd move toward a more solid solution such as a Cisco Pix Firewall and a Cisco IDS/IPS which are dedicated devices performing one job
I'll try and see if I can get some screen shots online, but don't take my word for it as my free time is very limited these past months.