I managed Check Point firewalls for years starting with Nokia IPSO-based appliances and then later Check Point branded appliances. No custom chips in any of them. All were pure software. The IPSO operating system owed its origins to FreeBSD and Check Point's SPLAT (Secure Platform OS) and later GAIA OS were both hardened versions of CentOS/RedHat Linux with a Check Point authored software package on top. No custom hardware anyplace. In fact, l frequently used both in VMware virtual machines in my lab although the IPSO VMs were a bear to configure because Nokia did use a custom NVRAM chip to hold some configuration info and you had to fake that out in the VM. I did it by using FreeBSD 7.1 to create a very basic setup and then copying the IPSO image on top of it using dd.
The biggest difference I see between pfSense and the Check Point products is the Check Point stuff can suck a whole lot more money out of the corporate treasury each year for maintenance and support contracts and licensing fees ... .
Later Edit: After thinking about it some more, it would be unfair to suggest pfSense and Check Point are identical in every way. Each offers its unique advantages. For a large corporate enterprise network, Check Point does have some nice management features that pfSense currently lacks -- mainly Check Point's SmartCenter server and all the firewall deployment, management and log consolidation functionality it offers. You can do some similar things with pfSense and third-party tools, but it's not as clean at the moment. Of course that Check Point functionality will cost you a rather substantial sum (very quickly rising into the 6-figures range in US dollars). pfSense costs you exactly zero US dollars if you support yourself, and still is very competitively priced if you purchase Netgate support.
However, out of the things I mentioned above, nowhere did I say that expensive product was any more secure than the free one. In terms of security, when managed by a competent admin, the free product and the expensive one are identical. The expensive one just offers some management conveniences.