I would compare it to what it costs new, also make sure you get that dealers warranty in writing. Good luck on your decision.
Bev

call or go to another brother dealer and see what they say about the same floor model.

My first machine was a used one and it has been a wonderful machine. I got the full warranty and never had to get it fixed till years later. It had been purchased and was only out for 9 months. The lady bought it back because she wanted a 6 needle. It was a Babylock Ellageo that sold for $5500 and I paid $2500. Still have it and it gets used a lot. Mostly now for regular sewing since I have the PR600II. Which in fact was a demo also. I wouldn't be afraid of it but ask for a demo first and the right to return it if it has something major after a few months. Good Luck

I would ask if the full warranty is from the day you buy it or from the day they put it into service as a demo (because it could have been a demo for a while). And, ask how many stitches are on it - that will tell you how much it has really been used. I would also ask to try it out yourself - I did this before I bought my Quattro (which was new but I test drove the demo Quattro and Elissimo before I bought). If you are happy with those answers, and with your test drive, I would buy it. I think $3,000 is a very good price for a "gently" used machine (and a 4500D is a really nice machine - big hoops, automatic jump thread cutting, etc. - I considered it when I bought my Quattro but I wanted the snowman functionality that does not come in the Duetta 4500D).

As a reference, I bought the 4000D from another user and paid 2500. I did not get any sewing feet or the sewing bed, nor a warranty. But I do love the functions of this machine. And I once you test drive, find the stich count etc., I would call another dealership even out of your area and see what that dealer has to say about the price. Since he does not have a 'bone in the fight', then he may be more apt to give you 'real' answers. Either way, good luck and have fun.