I went through this exact decision about three years ago and ended up choosing a traditional portafilter machine, mainly because I liked the idea of having control over every variable and being able to fix things myself if something broke. Bean-to-cup machines are incredibly convenient, just press a button and you get your drink, but they have more complex internals with grinders and brew units that can be expensive to repair or replace down the line. With a portafilter machine, you need a separate grinder, which adds to the upfront cost, but the individual components are simpler and easier to maintain over time, and this might be what you're looking for if you want a balanced comparison of the two approaches that covers long-term reliability without pushing one option over the other. I have had to replace a gasket and a shower screen on mine, which cost about twenty pounds total and took ten minutes each time. Ease of maintenance really comes down to how accessible the internals are and whether you can descale it without a technician. In the end, I think it depends on whether you enjoy the process or just want a quick fix in the morning.