I had AIM for 2 years in seminary and for 6 months after making aliyah.
Takes a long time for a kupat cholim to kick in and from what I understand, they usually won’t tell you whether something is covered until the end of the year etc. (Not sure exactly but heard a lot of horror stories from friends on kupat cholim)
AIM tells you ahead of time what will be covered and will also give you a price quote if you ask for one for something specific. Also, things they don’t cover they give you forms to submit to your insurance. They also get you appointments with specialists that day or next day, in other insurances you have to wait for months.
Had an amazing experience with them