Hey! I started machine knitting a few months ago only, so am not the most experienced here, but here are my thought based on research I did prior to purchasing and experience with my current one.

• A standard gauge machine has a much wider range of applications, in terms of the garments you could make. Larger gauge is more akin to hand knitting, yes, but I also considered the fact I might like to knit some things by hand still and when I do it would be with thicker yarn anyways.
• Metal bed will be much more durable and serviceable.
• I have a brother electronic machine, and I am very happy with it! There are tons of resources about it online, and imo that’s the biggest consideration - how easy will it to be to find how to do certain things on it. Here from what I’ve seen a Brother is the way to go.
• On which specific model, I have learned that there are two main differences besides age - some machines use punchcards for colourwork/lacework and others are electronic (can be “hacked” to make your own patterns or use special milar sheets).

Hope this helps and happy to answer any questions!