If you go vintage, look for Singer 15 type models. These will have side clamp feet, take the most common type needles (like "Modern" machines) and readily available bobbins. Almost all Japanese made machines (post WW2) are made based on the Singer 15 model. The older ones (50's-70's) are mostly metal and very easy to service. They do need to be oiled regularly, not like the "take in once a year and don't touch yourself" ones - they also need to be oiled but they want you to pay someone else to do it once a year for you.
Do not take any top clamp type, they are so varied and most take needles and bobbins that are no longer made. While they are fun and interesting, many of them have special threading and other concerns unlike the machines that were made using the Singer model.
I find it very interesting that before ww2 - singer was sort of an "odd duck" and after ww2, most became the same as Singer, and all the other variations disappeared. It's also interesting to note that Singer was also very similar to European machines - don't know if Singer copied them or they copied Singer.
And a Disclaimer - Singer once was the top - but in the mid 60's started declining.