My "top of the line" purchase was my Bernina 820 in 2011. It's been completely trouble/hassle-free and fabulous. NOT thread picky, touchy, or fussy at all, using threads from 12wt to 100wt in cotton, poly, and silk, and fabric from chiffon to heavy denim, knits, and of course lots of batiks and quilting cottons. Absolutely reliable, never been in the shop.
Would I do it again? My only hesitation is that I'm still no good at FMQ-not the fault of the machine, a lack of talent and practice on my part. I love my 820 for all kinds of sewing: piecing, quilting with the walking foot, garment sewing, basic home dec, mending, and FMQ (the stitch quality is great, I just can't make nice lines). But I really can't justify the cost, since I'm still not managing to quilt all my own tops. I do love it however, it's just more luxurious than my current quilting and sewing merits. On the other hand, I can hope to grow into it, that one day I'll FMQ well enough to need all that harp space. I would be very disinclined to sell it, even though it's more than I need by far.