I have a 39 year old 4.5 qt. KA.  It works fine.  I don't overload it or try to push it beyond its abilities so the only thing I have had to replace is the flat beater (the coating  decided to flake off about 10 years ago.)

This KA is my second one; I bought an even older one- vintage late 30's or early 40's- for $12.00 at an estate auction in the late 60's.  It worked fine for about 7 years before I got my "new" one.  The old one I gave to a friend and she used it heavily for another 4 or 5 years before it died.

Now, both of mine are/were Hobart made; so I don't know how well the newer non-Hobart ones will hold up. However, I wouldn't be afraid of refurbished/used one if your budget is tight.

For the attachments,  the grinder is the one I use regularly.  The other stuff just takes up space in my pantry.