Like many have said, buy the best you can afford. I recently was in your shoes. How I approached my search:
1. Identified local shops that sell machines. If I needed repair work I wanted a local dealer rather than having to ship the machine out.
2. Identified the features that I wanted - keep an open mind as there are features that I never knew existed. Your priorities may change.
3. Set a maximum price point.
4. Visit the shops and test drive each machine. Note the feel of sewing, the noise level, how easy is it to thread, practice with types of stitches.
5. Find out what is offered with purchase: classes, trade-ins, trade-ups?
I went to the store thinking I would try out a Singer- that's what I had 30 years ago. Ended up with a Viking Emerald 118 and love it. It has been a work horse. Being in between jobs, I have used the machine almost every day for 6-8 hours making quilts and other sewing projects. I have even FMQ a Queen size quilt despite the narrow neck.
Good Luck shopping.