I guess a lot would depend upon why you are interested in one, if it’s for your own use, then I’d look at your intended end use, use and ask myself how big of an image (physical dimensions) do I need to cut, both long term and short term?
Are you only going to cut purchased designs, or are you going design your own?
If you are going to cut purchased designs, then you need to make sure that the machine you choose, and it’s software, will cut desired files. If you are going to design your own, you need to make sure that the machine and it’s software will take, and work with, file formats you can generate. Always look at “Worst case scenario”, the biggest file/artwork dimension wise, that you would ever possibly need or want to cut. How complicated a file can your cutter handle, and what kind of memory capacity does your cutter need. Can you EASILY get new cutting heads, embossing heads, etc.? It’s easy to get yourself sold on something because of the low initial price, but if you can’t get new cutting or accessory head, updates on software, etc., then your machine is only good for the first few jobs. You end up with a really expensive paperweight/learning experience. What kind of material, and thickness, will your cutter handle or need to handle? Does or will your cutter work cross platform (Mac or PC), can you run it from a laptop? If you need to work remotely, like at craft shows, etc., this can be a make or break kind of thing.
Look ahead at your needs and limitations, and think of all of the steps that will be needed to get you to your desired destination.