What iSewQuiltArt does not like about this machine
Hmmm, the design of the ankle and some feet leave quite a bit to be desired compared to Bernina machines I use that have outstanding design of feet and the offset ankle for their feet for embroidery and quilting.
The Pfaff ankle sits down low, behind the darning foot, and obstructs a lot of vision when working backwards. I am surprised they do not make an alternate ankle to overcome this. I saw once Patsy Thompson in an online video sliced through her ankle to remove the offending part where the foot clips on,pe of the darnning foot which is rectangular. I do think this would be necessary if you planned to buy a Pfaff and to do a lot of freemotion work with any degree of precision.
The actual darning foot is made of plastic in that area and it is quite thick which can distort vision. I find this less than ideal. But since I see this machine as a machine to meet a temporary need at at that pricepoint it was my best bet for a decent stitch quality, I put up with it. It does annoy me but I do think if I decide to keep it it would be more for the dressmaking side of sewing than for quilting or for the kids use. I think for that foot design limitations I am experiencing right now would be less likely to come into play. At the end of the day the other feet are designed well enough to offer function that is needed for things like zig zag satin stitching, blind hem, zipper application - the sorts of things you do often when sewing clothes.

There is a half down position for freemotion work that I am still getting my head around, it leaves the foot in a half up position which can for freemotion embroidery produce some wiggly stitches as the fabric can tend to flag up the needle. I do prefer to have my foot closer to my working surface for freemotion work rather than have no ability to adjust the height of this foot with the set up Pfaff have chosen to employ in these and some of their other machines from what I have seen from quilting friends. It is irritating to have stitches be wobbly when I am highly skilled in freemotion work and know it is not anything I am doing different to my usual working style, it is absolutely the machine producing the difference in stitch quality.
The tension dial is a little awkward to alter, it is a little tight and sits in a strange angle in the front of the machine.
The last guide above the needle is a very tight space and I have found that many of the specialty threads I run with success in my other machines can shred at that point. The little metal clip is very tight and it is annoying when threading things like rayon or fine cottons to find they snap whilst "flossing" the thread into place as the manual suggests you do. Once you manage to get the thread in there though things work well enough.
One thing- and bear in mind this machine is built to a certain pricepoint, and built in China, the area surrounding the hook and the little spindle on which the bobbin case sits are plastic. I have no idea how long this will last. I do like machines that have as much metal as possible in this area as I tend to hammer my machines. Although of course I am aware that not all plastic is bad and that there are certainly durable sorts of plastics around...I am just not sure what sort of plastic there is in the bobbin area. Something to consider seriously if you are a constant sewer who sews for hours at a time.

Be aware the buttonhole is manual but has one of those sliding buttonhole feet. Although there are different buttons to press for the different stages, you must set and alter the stitch width and length as required. I am spoilt and do like my automatic buttonholes for things like making shirts where I make buttonhole after buttonhole and want them all exactly the same. Buttonhole capability was completely irrelevant to me for purchasing this machine however as I do not need to produce a buttonhole on my work samples for quilting.

Lighting is OK, but could be better. A second bulb on the inside of the harp near the right side of the needle would be worth having to reduce shadowing. Consider I am totally spoilt with CFL or LED lighting in my work machines however. I think the existing lighting is sufficient for me to work by but if I do a lot of night sewing then additional lamps would be useful.

On balance the negative things for me can be worked around or may become less important to me if I do decide to keep it in the long term. Which if I do would be used to have on the side for fun dressmaking and do not make buttonholes on it. It may be destined for the kids to use if not or I may sell it on. However, I just don't see any reason to fuss around with making manual buttonholes when my other machines make absolutely gorgeous buttonholes automatically or with minimal fuss. That's why the machine being totally manual is not a deal breaker for me but it might be for you if you don't really love making manual buttonholes.