My guild has a stitch regulator for our LA machine. The other LA in our tiny town does not. Ours is built in. It can be turned on or off. It speeds up the stitching when you are quilting rapidly, slows it when you are moving more slowly. The people I know who are real experts hate the regulator, but they are better moving the machine at a uniform pace than I am. The regulator is NOT foolproof. If I go way too fast or slow, I mess things up, but when my disability allows me to use the LA, I do appreciate the regulator.
I know some Janome models have the option of starting the machine and having the needle run at a uniform rate without any foot pressure, which is NOT tha same as a LA stitch regulator. Frankly, that scares me. It would be way too easy to be seriously hurt by it it you get distracted, which I sometimes do.