I agree with Alex - the Iba1 staining is superior and it may due to the quality of the antibodies. However, it is worthy to note that Cd11b/Ox42 is a membrane protein, whereas Iba1 is expressed in cytoplasm. Therefore, Iba1 produce a more plain and robust signal in section with small thickness. A general complain of using Iba1 is that the most popular antibody from Wako (#019-19741) is only made in rabbit, so many researchers have used Cd11b made mouse as an alternative in double staining. However, we have now successfully tested the Iba1 made in goat from Novus (# NB100-1028), which is not as good as the Wako antibody but still results in much better staining than the ones obtained with the CD11b antibody.