I also have the 5.0 and love it. I think one of the new features the 5.2 has added are the "stacking stitches".
I bought my 5.0 from my local Pfaff dealer, so therefore it has been serviced more than once, general maintenance mostly. I think one time the needle threader needed adjusting.
Just make sure you have the owner's manual, for it is definitely a reference tool when you aren't sure about a feature. You will love the IDT, a Pfaff exclusive.