@Sewbee - I was like that before I ordered my 720. I actually told the dealer I wanted one, so they put it on order but didn't take delivery from Bernina, and then I dithered so much that Bernina had sold it when I wanted it. It then took me another 6 months before I placed a firm order. Of course, I then had to wait 4 weeks for Bernina to build it, but it was definitely worth it. (I could have gone for the 770 or the 790 but I didn't want the wider foot or the dual feed. I'm very happy with the 5.5mm foot and my walking foot.)
I don’t want the 9 mm either. I much prefer the 5.5 mm.
I honestly think trying to make a decision, first of all, about whether to go ahead and actually buy it, but also which machine if any to trade in, is worse than actually doing it.
I know me, though. I always go through this before an expensive purchase. It usually takes me about three months before I decide what car I want to buy and this is very similar. I have to be absolutely sure it is the right thing to do and also be absolutely sure about which one to trade in, if any, before I will go ahead with it.