... exploded format means all dimensions and lines are separate segments ...
That's because PDF (a popular plot file format) does not contain intelligent objects like dimensions. The PDF format does not even contain a circle object, it must be represented as four bezier curves. Everyone should lower their expectations of what a PDF is going to produce when opened in an application like AutoCAD, regardless of the conversion software.
Terry is completely correct.
If you really really really need valid cad files from your PDFs, and your clients refuse to provide them, then the only completely reliable way to do it means re-drawing. If you version of CAD supports PDF Attach, then use them as backgrounds and trace them (correcting on the fly of course, be cause PDF, since it's a plot file lacks the positional accuracy of a CAD tool). If your version does not allow you to directly attach a PDF, then conver them to TIFF format, attach the image, and trace that.
Don't forget to include the extra labor when you bill your clients.
Implied, of course, is to check the contract first: you may be entitled to those CAD files in the first place. If not, time to review how the contracts are drawn up and approved.
I have used the trial version of Print2CAD and can verify it is far superior to any other conversion software available for .pdf files, directly to .dwg file. I found no shortcomings while using this software. I recommended it to our management for future consideration if we run into a situation where we need to convert more than just a few .pdf files.
I realize that this is an old topic, but I have another suggestion. I found AideCAD's (aidecad.com) PDF to DWG creator did a good job when I tested it out. It creates a DXF file, although a check of the web site this morning indicates that they now offer DWG as well. Personally, I would stick with DXF as an open format, rather than a reverse-engineered DWG. Note that I have only done a few conversions, none of which were 3D or extraordinarily complex, but it is worth a try. Check the first few conversions carefully.