I have a Husqvarna Designer 1, which is an old machine but is still great
As with any machine you need to research them before you purchase....also what budget do you have as they can range from about $800 - $5000....the quality on the cheaper ones can be excellent..they just don't come with all the bells and whistles.
1. Only the more expensive ones have colour screens and allow you to edit on the machine..ie make smaller or bigger,rotate etc.....This is a real nice to have but you can do that on your computer before transferring your design to the machine.
2. Hoop size....how big do you want to embroider, some machines will only accept small hoop sizes...you will need to check the maximum hoop size.....do you want to do long borders...some machine will be capable of this others won't......I think I have only gone above 5x 7 a couple of times
3. connection and transferring designs....do you want USB, very easy to use or are you happy with a card reader.
4. Software...You do NOT have to buy expensive manufacture software, there are some really good very easy to use programmes that are very cheap in comparrison and are great. Embird and SewWhat are the ones I use.
Threads and backings aren't cheap but it is wonderful just to finish a quilt with a personal embroidered message or anything for that matter.
Let us know what you get and have fun