I don't think that scalability is a pertinent criterion for firewalls because they're hard-coded by the ASICs that go into them. When we rent a firewall to a customer instead of selling one, that customer has an upgrade path available. In this regard, it is scalable because we can switch them to a larger model if they outgrow it. Otherwise, it's limited by the ASIC.
Firewalls Upgrade Path Reviews
Showing reviews of the top ranking products in Firewalls, containing the term Upgrade Path
SonicWall NSa: Upgrade Path
Cisco Firepower NGFW Firewall: Upgrade Path
Paul M Wojciechowski says in a Cisco Firepower NGFW Firewall review
Network Engineer at a pharma/biotech company with 201-500 employees
From start to finish, including production rollout for other areas, deployment took roughly one month. We did it all in-house.
Some maintenance is required involving security patches. Cisco is really good at deploying those or not deploying those, but putting those out and having release notes and upgrade paths and just the information behind all of their patches. Cisco does a really good job with that.