The trick with these kind of gigs is making sure that you're being asked to perform the right kind of work - honest assessments of whether someone sustained a disabling injury. The current economics of medicolegal work make this possible only when working for the plaintiff.
The insurance company/defendant will always be looking for testimony that will help them deny a claim. OTOH, while some plaintiff's attorneys will want any testimony that will support their case, in my experience more of them want you to help them figure out whether the case is legitimate in the first place and thus worth the (significant) continued investment in pursuing it. The reason for this difference is just in how the system works. Defendants will always be involved with a case and looking for anything to help them, while the "rate limiting step" in the injury law system is in plaintiff's attorneys - they have to carefully pick and choose which cases to invest 5 figure expenses into litigating or very quickly go out of business.
You can see this difference by looking at the quality of evaluations from a physicians lens when you get involved with a case like this. The docs who do insurance company work are virtually always hacks - they're so far into the process of having sold their soul that they can't remember how to document a proper H&P that actually supports their conclusions. They are generally not actually practicing medicine anymore. The evaluations from the plaintiff's side are generally of better quality and tend to be performed by people who are still actively practicing and thus have a reputation and license to maintain.
Ask the hiring party what the goal of the evaluation is and make sure you will have true independence to make an honest evaluation. An honest plaintiff's attorney will accept that happily.
