I have sewn on it, and if I could justify spending that much money on a machine I probably would have done it. It does perfect stitches, all kinds of auto functions and gadgets you would expect from a top model these days. I have a suspicion Bernina quality is a notch better than most if not all the domestic brands at the moment, due to the consistent devepment team and quality testing that is their own. Nothing is perfect, there will always be a certain amounts of pros and cons. I doubt you can by anything better though.
On the other hand, I've not grown dependent on auto threading, built in walking foot, needle up/down function, knee lift or the latest computer features. I fell for the charm and quality of an old cast iron straight stitcher, along side a basic zigzagger with a few extra stitch patterns they serve my purpose very well. I feel I can do anything I want with them and the old straight stitcher is a joy to work on, smoothest machine I have ever worked on. I have accessoried it a bit; a buttonholer and I newly ordered a walking foot. The only think I would benefit from on the new Bernina is the stich regulator, it seems totally idiot proof and perfect for both beginner and experienced quilters alike.
If you are very ambitious with your quilting and want the latest technology and features, I doubt you can do much better than the new 700 series. Are your old machine beginning to struggle?