You could ask a similar question about cars: Do you think I should buy a Dodge, Chevy, Toyota, or Ford? I'm afraid the answers would be about as meaningful. We all have our favorites, mostly because the ones we ended up with meet our personal needs. However your needs and wants will probably be different. I always recommend you check for the best local shops first. That will narrow the list significantly. For example, if there isn't a good Bernina store nearby, it probably should come off your list. Then go to each of the shops with samples of what you normally sew with - piecing, FMQ, garment fabrics, home dec. If you do buttonholes, come prepared with samples to do those one. Spend some significant time with your options. One of the machines will probably "speak" to you. BTW: If the shop doesn't want to let you just play with the machine a bit to try it out, move that shop to the "not very good" category!
As to purely personal experience, I love my Berninas and my vintage Singers. I value perfect straight stitches and heavy-duty metal construction so those fit my style. But note: Your style may vary completely!
Pam