I would give them 4/5 (which is basically the best, no one is perfect). Good product in general, pretty responsive and kind customer service and the security is as decent as I have seen. I would never back up the idea of undetected because there will always be times when programs get detected (they have been detected but work quickly to get the program back up unlike other providers). One knock would be communication, it could be quicker but hey they are human. I would definitely recommend them.
A note for all on the claim of "UD." After years of using various chairs, I have found this means different things to different people. Outside of truly private (high-priced) programs, getting a UD program is not possible. You will be caught eventually. There should a "using programs basics" that reminds peeps of this, so that expectations are not set so high that they feel comfortable with using their main account with a program. Good providers will work with their customers and work on their programs during ban waves and the like. No one should expect never to be caught. That is stupid but I've been there and learned, like many, the hard way by losing a main.
Good luck to all. Use Aimex, they good. That's all.