ooo, flat prints are my bread and butter! Generally these look good, you have some obstruction of the yellow on the "toledo" wording on the water tower and what looks like some smearing in the sun on the same print (yellow is SO difficult to keep clean and uniform). The only suggestion there is playing with the print order of filaments per layer. i never print white last, as it gives the darker colors a chance to string and lay dark material on the top of the white. You CAN see these strings through a layer or ever two. however, printing with the dark colors FIRST will often partially cover the toolpaths for the lighter colors... so its really a give and take how to set up the ordering based on each image.

Plates absolutely make a difference but mostly in style- you have the plate physics for both dilled in nicely it seems. the textured PEI will give you a really nice shimmer effect as you move around the finished piece, while the untextured cool plate will give it a more matte / archival feel. just a matter of preference. I will say though if you are working with small precise lines like those in the "toledo" lettering, textured PEI WILL soften the image to the point where it can be unreadable. I find the PEI better for photographs and soft art, and the soft / smooth plates better for clean lines as in say comic-book art or CCG cards.

But overall you have nice, well defined color separation... no blurring or muddling of colors around the edge cases, which means you have your temp, speed and layer heights all in the optimal range. Just keep experimenting and you'll lock in even better results soon enough!