I've got two very old Berninas. I love that I can open them and do a lot of cleaning myself. Though did get a little frustrated this summer when the 801 quit working mid-stitch. Turns out, that when I took it in after purchasing off eBay for maintenance, it was so clean (I had just taken the 'welcome to your machine' class at our LQS) that she didn't oil it, thought it was done. Thankfully it was just a lack of oil that froze the machine. I did find a surprising amount of lint inside when I first learned how to open her.
I need to bring my 830 in for maintenance after the holidays. A Craigslist purchase, so I'm sure there are some areas that will need oil that I don't know how to reach.
Cheers, K