Better you understand it, less errors you will make later configuring it.But also it's important, what it actually allows you to do - and that you will find out, when you have the product in your hands. One should evaluate the different solutions and find the one, that is most logical to manage. Most will offer a Web management and command line interface, while WatchGuard also comes with Windows management tools. There is also a price/performance difference and of course differences in the management. The biggest difference is what different vendors include in their basic packages and what you have to purchase in addition to get a complete solution. Most of them will have a model, that would suite your needs. I'm a WatchGuard fan, but other UTM vendors also have good products that are liked by other people. They come with a price tag, but not having an optimally secured network may become far more expensive on the long run. In your place I would look at some SMB UTM solution. But than there is a problem with the quality of these free services, support, you may run into compatibility problems. In most cases these are opensource or free. It's an opensource platform, that is contributed with addon packages for different security layers. There are many vendors for these, like WatchGuard, Fortinet, SonicWall, Sophos, PaloAlto. These are called UTM and/or Next Generation firewalls. Modern security solutions use different security services to provide layered security, where the packet filtering is only one of the layers. In some usage scenarios this is completely enough, but not what any security expert would recommend for a normal business network today.

It is more a connectivity solution, than a security one, even if it can provide some basic security with the packet filter firewall.

Mikrotik is a great low cost router with a packet filter firewall. As you already found out, these are two different categories of solutions.

Mikrotik pfsense