Should work on every x86 based SG/XG, OPNSense runs fine on my XG105. More on reddit.com

from everything I understand this was just a SKU thing. When ordering the SG came with an older version of software and the XG had the newer version. Hardware wise these are the exact same. More on reddit.com

One thing you will face with sizing based on publicly available specs like these is that they are usually measured with fairly specific lab setups that might not 100% reflect the actual throughputs as they are a measurement of absolute maximum throughput at ideal conditions(the methodology is briefly explained in the full datasheet), you might get closer or further from that 1Gbps depending on your environment and use cases. This is why Sophos usually goes through their partners for sizing and sales, as a lot of factors need to be determined beyond the public specs - there are also internal sizing guidelines for those devices as well. You might be able to find actual sizing guidelines that will expand the specs a bit into more "realworld" applicable specs, though it's not a public document some version of it are floating around. You need to decide what features you actually want to use as well - for example the NGFW throughput is only measured for the IPS and App Control modules and does not include antivirus or additional load of VPN etc. If you already have experience with a virtual XG Firewall you might actually be better off sticking with it, Sophos estimates about 10% overhead for the sake of virtualization, but you also need to compare what hardware you can provide to the VM. The XG 115 Rev3 model itself has a quad core Apollo Lake Intel Atom in it with 4GB of RAM, and if in your virtualization setup you can provide higher CPU power within the limits of the home license for 4cores/6GB RAM, you might be better off sticking with that. It's also possible to build your own bare metal appliance with a higher power CPU and just install on that. If you are buying through a vendor that would allow for a demo setup it might be worth giving a 115 a shot for the sake of testing, or talking to them about sizing, but see if you can outperform those appliances with a VM - you might come out better money wise. Another thing is that the current XG v18 throughputs are not yet fully tested, so the estimated throughput might change if you go with that version of firmware, it should be a bit better on v18 though due to some improvements. More on reddit.com

That the hardware gets EOL-ed shouldn't matter for the Home version, as it just "sees" a computer, not a Sophos appliance. Not sure about the UPS thing, rest should work. More on reddit.com