I have a Riccar that I bought when sergers first came out. I think Juki made the first ones for home use and the Riccar and a few other started making them. I loved mine and it still runs, my problem is I can not longer thread it. About 7 years ago, I bought a Viking and it is great, it is much easier to thread and does everything I need it to do.
Having said that, I would suggest you do as some of the others have said and go and try them out, decide what you need it to do and then make your decision. Good luck and have fun.