My "big" machine is my Janome 6600. I love that machine. I've only had it about 3 years now so I can't speak to its long-term reliability but so far it's been 100% reliable, even after my 9 year old niece spent 3 days playing with it!
It's not at all fussy about thread and I find it to be extremely easy to use. I would definitely buy it again if I needed to.
Backup machines...I did buy a Janome 3160QDC to be my portable and it's a sweet little machine too, but I've actually ended up using my vintage machines for classes and vacations the most. Not because the 3160 lacks anything, but just because I find it to be "fun" to sew on those old machines!