I think part of what you need to ask yourself are what your tastes are?
Are you a decorative stitch user? Do you like to adorn everything?
I think I've done well if I get the basic garment put together, so for me, utility is important. I have decorative stitches on my machine that I've never used.
Do you like ruffles and smocking? Embroidery?
For myself, I've come to the conclusion that I would be better off commissioning/hiring someone to do embroidered motifs for me - after considering the cost of the machine, thread, and patterns for a particular motif. The odds are very high, in my case, that I would never do another one again.
The needle down function is very helpful.
I bought three Singer 237 (or 327?) Fashion mate machines. They are very Plain Jane machines - forward, backward, zig-zag, and three needle positions. AFTER getting them cleaned, oiled, and adjusted properly, they do about 99 percent of everything I sew on an ordinary machine. The downer on them is that they are heavy. And they do a nicer satin stitch than my Pfaff.
If I were buying a new machine - and I do think it would be kind of fun to have a very top-of-the-line new one, but there is no way that I can justify it with my style - I would probably go for the mid-price range machines.
Buttonhole maker is nice to have, even if one doesn't use it often, The utility stitches are great to have.
This doesn't really answer your question. It's kind of like when I was looking at computers and I was asked "What do you want to do with it?"
I didn't know enough then (or now, for that matter) to answer that question intelligently. You may be at that same stage in your sewing career.
At any rate, I hope you find a machine that is reliable and does what you want it to at a price you can afford.