Really hard to know if you will be impressed by the 24-70mm compared to your 24-105mm. In my opinion, the EF 24-70mm f/2.8L II was one of the best lenses I've ever owned, much sharper than version one. But I bought it brand new from an authorized dealer. Used lenses can bring a lot of variables to the equation!
As docsmith suggests, the images you've provided might show you something about the lens you (and possibly dozens of others) rented, but without helping us form an opinion.
It's very important to take standardized test-shots with any lens you purchase--before your return window expires. Only you can decide whether the sharpness and other image-quality aspects are satisfying enough to declare the lens a "keeper." Sure, we can get a general idea from looking at posted samples, especially comparing one lens to another, but you can see the originals straight-out-of-camera. This doesn't apply only to forum members' posted images, but even to the best online reviewers. Unless we download sample RAW images, a posted jpg has too many issues with compression, processing, and technique to help make informed judgments.
For example, one of my favorite review sites is the-Digital-Picture.com I like what Bryan writes, but I've never found any of his "real world" sample images help me learn much about a lens. However, his comparison shots of test-charts do help give an idea of how sharp one lens is compared to others, and how sharp the center quality is relative to the corners. (And even then, we are seeing comparisons of his copy of a lens compared to his copies of other lenses.)
Not trying to brush you off or just say, "You are on your own," but until you have the lens in hand and you have tested it, the best I can say is "Good luck!"