The homepage of Comixology is barely friendlier to Marvel than Amazon is. Here, it's Image Comics that seems to dominate, with two of its series, The Walking Dead and Saga, occupying ten of the top twelve selling spots. The remaining two are DC titles. Marvel again didn't crack the first page of 25 results, with Hawkeye #1, its top seller, coming in at #26. Note that these results were gathered after Marvel and Amazon not only announced the deal but promoted it right on the comics & graphic novels section. There's been plenty of time for the news about the Amazon deal to percolate through the marketplace, but digital buyers just don't seem to be flocking to Marvel in really large numbers, whether on Amazon or on the Comixology app.
T Campbell has written quite a few online comics series and selected work for Marvel, Archie and Tokyopop. His longest-running works are Fans, Penny and Aggie-- and his current project with co-writer Phil Kahn, Guilded Age.