Is harbor a lower tier residency?
I would not call any California DR residency lower-tier in terms of matching; even the community programs fill with graduates of top-25 medical schools. Along these lines, a program's matching competitiveness can be approximated based upon the medical schools of its residents. For example, UCLA's residents are almost all from top-25 schools, Santa Clara Valley Medical Center's residents are almost-all top-25, and UCLA-Harbor's residents are almost-all top-25 (with a few top-50 schools). For the latter, see:
Residents - Page 5 of 5 - Harbor-UCLA Medical Center. In contrast, mid-West, deep South, and isolated New England community programs have a large complement of graduates of the top 50-100 medical schools as well as Caribbean graduates. I don't include osteopathic or foreign medical graduates in my thought process because some programs simply don't consider DO or foreign graduates, despite their qualifications.
With that said, matching competitiveness should not be a primary concern. Having gone through this process, the
only two things that you should care about are:
1. Will the program set you up to obtain a fellowship in the region you want to live and work long-term?
2. Could you stand living there (i.e. not quit) for the 4 years of training?
The answer to the first question is found by looking at where past residents matched for fellowship; look at the link above for UCLA-Harbor. If you want to do Body or Breast imaging in Southern California, then UCLA-Harbor works well, but if you want to do IR in Southern California, not so much (only 1/5 residents who applied to IR matched to IR fellowship in California)! Obviously, if you don't want to work in Southern California...probably you shouldn't go to UCLA-Harbor.
The second question is somewhat mute since you could live on the beach while going to UCLA-Harbor, but it's an important consideration when thinking about going to a top-tier place in an undesirable location.