I've used both Print2Cad and AutoDWG for PDF conversion, and depending on how the PDF was created directly affects what you get. If it was generated from a drawing-type program (like Dcad, Acad, etc.) it works pretty well (especially Print2Cad); if it's a scan of an old hand drawing that has a lot of background, lots of curves (like leaders) and very distinctive lettering style it's not worth using. It's the old saying of "garbage in/garbage out". I haven't tried it with a JPG but imagine that it would be a similar type of result - the cleaner and clearer/crisper the image the better.
If you've got a file (single sheet) you'd like to send me I can run it through Print2Cad and see how it does. PM me with your contact info and I'll give it a go.
Alan T. Hendry, RA
Intel i7-6700 (3.4GHz) Desktop, 32GB RAM, 3TB HD, Win 10 Pro 64-bit, DC 17, 18, 19 & 20 w/ latest beta update
Intel i7-4702 (2.2GHz) Laptop, 16GB RAM, 1TB HD, Win 10 Pro 64-Bit, with DC 16 and all of the above