The anidees AI4 does look like a tiny version of the AI6, which is a good thing as everyone who liked the larger variant but was waiting for something more compact will be happy. The mATX tower chassis was sorely missing in anidees' line-up, and it is good to see such a nice implementation of it. While the interior boasts the "dreaded" side panel for hard drives, anidees has managed to implement it in a solid fashion that won't have you worry about incompatibilities with long GPUs, for example. Unlike other cases with a similar layout, the AI4 also offers the full width of a mid-tower and, thus, the ability to hold a 120 mm cooling fan in the rear. This allows for large CPU coolers to be used within.
The size naturally does bring some issues with it. Things will get quite crowded quickly and you will have to get creative in keeping cables away from fans to ensure airflow is unobstructed. That said, if you were not aware of such drawbacks for a case of this size and are disappointed, you should have done your homework (or read this review) beforehand. Small cases offer less space—that is a reality you have to deal with if you want such a case.
Luckily, the anidees AI4 scores points with its compatibility, build quality, great feature set, and three pre-installed fans at around half the price of the AI6v2. This compact case is better value for your money overall, though we should not be comparing apples to bananas. If you look at other mATX enclosures out there with the same type of layout, the AI4 is in a league of its own when it comes to quality. That said, it also costs around 20 euro more, which is a small price to pay for some peace of mind.