Building Reliable Systems
While everyone wants to get a cheap Raspberry Pi or old computer and install ASL on it to make a "junk box" linking repeater controller, others want something they can put at a site for years without needing to worry about it. These users are less concerned about price, as their sites may be inaccessible for good parts of the year. Or like myself, simply not have the time to go fix it when it breaks.
Reliability of the controller/install falls into two major segments, hardware and operations. Hardware is the choice of system parts and operations comes down to how you monitor and maintain it.
Hardware
ASL can install on intel/amd based servers or on arm (Raspberry PI 3/4), and each has it's use. RPi based servers typically are used for a single node, and work best at sites which are easy to access. RPi is cheap and if it fails, it can be replaced for under 100 USD. Intel based servers tend to be in a 19" rack mount form factor, give the ability to use real SAS or SATA SSD's and have out of band management options. These servers may optionally support the Quad Port pciradio interface card. This card is basically a 4 port simple usb interface, but designed to slot in a PCI bus.
Intel servers are a great choice when you need to support more than one node per server or will be doing lots of linking. The newer RPi4 has blured these lines a bit due to 4 or 8 GiByte ram options, and impressive SMP clock speeds.