As for scalability, it's good too. But it will depend on the type of wifi controller that is installed in the company. In our case, it is the 5520 and it supports many simultaneous clients and controls more than 1000 APs. Without the controller the AP is standalone and loses some advanced features and it is necessary to make the settings manually.
Cisco Aironet Access Points are made for large environments. There are multiple models to choose from depending on your budget and requirements. There are outdoor models as well which can be implemented in harsh outdoor environments. They are also scalable and can be increased as per growth of a company. the controllers support large number of access points, even the lower level controller supports upto 150 access points.
Scalability of using Cisco 2800 series AP's is good as using it in a Cisco Environment like with Cisco Switches it helps a lot in troubleshooting and Cisco ISE provide great functionalities and features of wireless users control.
They are flexible and scalable in their own ways. When paired with a nice Cisco WLC then you get the full package. They have super long range and can host tons of clients. They can be paired with other models in the same system without issue. And doing a large rollout is made easy with Cisco's easy to use software.
Those APs offer a good value for good wireless performance. It's really nice that all external antenna and mounting kits are compatible with the previous Aironet series (like 2500/2600/2700) so it's quite easy to get those APs replaced by the 2800 series. Also, the design is a bit more robust, so it's good for a factory environment.
I would assume that most people getting a large amount of these AP's would also be investing in a Cisco controller that combines all the management of these into one simple to use location. That's where it truly shines when you can deploy 10 of these in under an hour because the controller makes setup so simple.
The Cisco Aironet 2800 Series Access Points have been highly scalable, in particular with Cisco-rich environments. This is due to Cisco's DNA Center. Normally, it would take more time to deploy and configure multiple new APs on a network. Cisco DNA Center integration costs less time to configure all newly added APs to the network.
I gave this an 8 because we have found the Cisco Aironet 2800 Series Access Points to be very scalable when paired with a Cisco Wireless Network Controller. We are using the Cisco 8540 Wireless Controller to manage all of our 2800 APs at both of our corporate offices. We are able to push out new wireless policies and firmware upgrades easily using the controller.
This is probably the best part of the Cisco Aironet 2800 Series Access Points lineup. They are designed to work seamlessly with the wireless LAN controller, and what you get (after some initial configuration) is an amazingly easy rollout of APs. You can literally plug these in anywhere on the network and the wireless LAN controller will identify, update, and push the appropriate configuration to it within minutes.