Your question is kind of a complex one and may depend on what you want your career to be after fellowship. I work on the faculty of a fellowship program and have done so in this capacity for about 6 years. In my experience there is a tremendous range in regards to the programs out there. Sometimes those with "prestige" so to speak, fall short in some aspects of training. To be fair, one year for this type of training is never adequate but there are a handful of basic core aspects most people will need. As a practical matter I would focus on those programs that are strong in report writing, because you'll find out soon in this field that the majority of cases don't lead to testimony and your report may be the only thing you have on the record in a case. Experience in actual testimony is also of prominent importance, as are the diversity of cases (civil, criminal, etc.), diversity of the types of evaluations performed (competence - civil and criminal, risk assessments, "insanity" evaluations, etc.), access to the director, and the degree of mentorship offered upon graduation (strong programs will offer lifetime mentorship for graduates). I am sure I am missing a lot at this point but those are a few off the top of my head.
Also, consider lifestyle as well. Find out what the schedule is like and your responsibilities. Some programs will primarily have fellows staff inpatient forensic hospital units- which can be an important experience in regard to dealing with that specific population, but for which 90% of the work you will already have expertise in. Basic patient management of this kind should be limited. So, find out if this is the case for the program you are applying to, and whether or not you'll need to get "coverage" for vacation. IMO, a strong program will not have "fellow dependent" service requirements. Fellowship should have flexibility and respect that, at this point in your career, you may have a family to take care of and may relish the thought of continuing to be pushed hard for simply an optional "5th year of residency" (especially when you could just as easily make 4-5x the amount by becoming an attending instead).
And lastly - see if they will give you time off (and pay expenses for you) to go the AAPL Annual Meeting and take the review course.
I hope this helps a little, but I am sure I am missing a lot of things I could be adding. Please send me a private message if you have any questions of would like any advice.