One of the crucial issues is repairs and training. Part of the cost of a machine from a local dealer is for training and classes. If bought elsewhere, the owner must pay for classes.
Since 99% is straight stitching, that's the most important issue for me. Free motion quilting is a form of straight stitching. Any mechanical machine can do this. The size of the harp is important for FMQ.
Brother 1500SL Nouvelle is a work horse. Turn it on and it's ready to go. Has needle down, threader and cutter. It has a device that works like an even feed. Less than $1000. This is my 99% machine.
If you want a machine for traveling- get a light weight and expect it to take some beating. Most of these do zig zag. With these 2 machines you may have all your needs covered.
Machine embroidery is loved by some and never used by others. And it's expensive, but you already have that capability?