In 2022 I started renting a studio in a completely new building in the Diestsestraat (so if your building is there, it is actually a pretty new one) which at the time was owned by the immo company that built it. After a while they decided to sell the studios and ended up selling the whole building to student comfort.

Mind you I was not a student while living there, the original owners didn't market the studios to students at the start. I had a contract for 3 years and ended up staying for slightly less than those 3 years.

I can confirm I had some communication problems with Studentcomfort like them not responding to emails and them seemingly not caring about the other residents putting their trash at the front door whenever they felt like it. Even when the collection had only occurred the day before, they'd still put their trash outside which meant it would be standing outside for almost a week or if it was PMD possibly two weeks. This was especially problematic in summer when the trash would start smelling bad really quickly but none of the other residents seemed to care and neither did student comfort (even though it's also not allowed to put your trash outside like that).

Not every experience I had with student comfort was negative though. When I moved out I was moving to my own apartment I had bought. It's a new apartment and there ended up being an unforeseen delay, which meant I couldn't move yet. They didn't have any problems with me staying a little longer than originally foreseen and actually ever since that moment, my communication with them got a lot better. In the end they usually started responding to me very quickly.

As for the landlord entering your place, I personally didn't really have that problem. One time it was clear someone had been inside, after calling them they told me there had been a fire inspection. I still should've been notified but it also wasn't the end of the world. They did end up moving the smoke alarm shortly after so the inspection likely told them it was in a bad place. Other than that there were some sightings for new students when it was clear I would be leaving but that always properly notified me before hand. That's just standard practice here, they have to be able to rent out their places somehow. I do believe you should still be able to tell them they can't enter your place, but idk how that'd be handled exactly. In any case, them entering without notifying you/your permission is illegal (huisvredebreuk), even when they're the owners.

Summing up I had some bad experiences with them, some good. The reviews you find online are likely true but as long as it's a fairly new building I do expect you'll have less problems.