I only quilt also, but I do like some of the heirloom stitches on my QE4 and Pfaff Performance 5. It's no secret my first Pfaff (Quilt Expression 4.0) was a lemon - it was replaced by Pfaff - and I hated it. Once we bonded, I loved it and when I saw the Performance at a quilt show, it was love at first sight and I've never regretted it.
As someone already mentioned, the built-in walking foot (IDT) is bliss. In fact
still having to add a walking foot to the more expensive Bernina is one of the things that stopped me buying one.
As well as the auto-pivot (no need for presser foot lifter or knee lift) which just starts sewing when you depress the foot pedal (Look! No hands! Lol), I like the Sensormatic mode for FMQ, where the foot just 'hovers' over the quilt sandwich instead of hopping up and down.
There's a good YouTube video
here that you can watch from the comfort of your armchair (it's over an hour long). I suggest you make a list of what's important to
you and take it from there. Good luck!