FreeNAS is well suited for most storage serving scenarios, whether it be for an office file server, backup destinations, data replication across the internet, or as backend storage for virtual machines. It can serve various types of clients via a plethora of standard protocols and can easily integrate with existing infrastructure using LDAP authentication and so on. It's pretty simple to use (it helps to have at least a basic understanding of the underlying technologies) and almost maintenance-free. One scenario that springs to mind that it may not be appropriate for (yet) is as S3 storage. However, S3 functionality was added in a recent release and may have improved greatly since then. I'm sure it will eventually work very well for this.
iOS works well when you want solid control over institutionally-owned devices. This generally works best when you play by Apple's rules and buy through them and use Apple School/Business Manager - so if you're going for a BYOD model, this probably isn't the way to do [it]. There is a wide variety of management tools, but bear the costs of each in mind.
In all likelihood, common users will either already have experience with iOS on their iPhones, or will pick it up quickly. The UI is generally simple and mostly visual. Power users, on the other hand, may feel constrained by the inherent limitations built-in. Root access, terminal commands, and deep customization are not really to be found here.
Lots of help articles online for just about everything under the sun. I have never personally had to engage Apple's support team to comment on their helpfulness.
FreeNAS effectively uses all resources really well and it is highly recommended for in premises NAS. It has unlimited ROI as it is really free and open-source. The only payment we need to pay is when we need any support from those guys. FreeNAS helps us to effectively do our work with the legacy systems as it manages all the components really well. FreeNAS although rebranded to TrueNAS will still be there until our legacy systems run.
The software updates have a wide coverage for iPhone models and I love updating software for additional features and/or improved software stability. It has also genuine feel of the phones they offer. Easier to set up and use. It helps me do more productive tasks. If I have the latest phone model, I would have additional software advantages that are already included in my OS.