A site, of roughly comparable size to mine (fewer uniques, more page impressions) wants to give me lots (hundrends) of effective links (probably by copying lots of my content and putting canonical tags on it that point back to my site).
Is there a lot of extra value in this compared with a a few links from the same site?
Is it worth giving them back lots of links in order to get this?
If they want to republish some of your content they should be giving you fully spiderable links wherever your content is used, and the deal should not include any obligation for you to link to them. Links in exchange for content is already a good value for them.
Remember that you'd be incurring a risk that they'd start outranking you for your own content.
Consider the pros and cons very carefully. What's the value for you in all of this?