I think if you ask procurement, they would always point to a low cost MDM but to be honest, this is often not the best solution. Why?
Often such MDM does not provide the functionalities you need or even want. So This should be one of the first things: What do i need (and want) to do with the MDM now and in future?
And please don't forget about the "future" part here as changing an MDM is nothing you will or want to do often (that can and will be a big effort), most likely you will stay with your first choice which it makes even more important to choose the right one directly from the start. And this also includes maybe managing not only Android devices but maybe iOS, Windows, Linux or ChromeOS or anything else (instead of having one system each for example).
Next thing to consider is in my opinion: Can the MDM handle the amount of device we want to manage (and still leaves possibilities to raise that in future easily)?
You will be surprised how fast this number can grow, so don't consider too less devices.
Can the MDM work how we want it? That means the server location (On-Prem, Cloud) but also how long it takes a change to be in place or is the UI user friendly and so on. Or can it use SSO for a better user management,... So you should consider to do some test instance from possible MDM's you would choose from.
And last but not least of course the prizing but in my opinion (depending on the companies possibilities) this is the last point to look at at if one of the other things to be thought of may cost more if not considered correctly or ignored because of the prize and needs to be handled i a different way which again costs a lot (another MDM for different OS or function not included, so manual task taking a lot of time,...).
It very depends on use cases in my opinion.
Example BYOD: If staff just needs to be provided with apps and maybe Wifi or other settings but should be able to work with their private phone, then i would choose BYOD.
Example COPE: Same as BYOD but if device is provided/owned by the company, i would prefer COPE.
Example fully managed: If devices have to stay in the companys environment (Stores, warehouses, trucks,...) and not to be used for private stuff, i prefer fully managed (we mostly use this atm).
Example fully managed - dedicaded device (kiosk): If you need to provide the device very locked down because customers have access to it to order something or similar things. Or if you need to provide a very static and stable device like in warehouses to limit the risk of usage issues, i would prefer a dedicaded device.
In general (from IT perspective) i would always choose the one with the most possibilitys regarding management but always keep in mind it has to fit the best to the relevant use case.
Some people think that BYOD means "managing the private device" and because of that they don't want it but that's not true. BYOD means providing possibilitys to work with a private device instead of heaving a seperate work device in hand.
