I can only speak about The Chicago School, and only a little about it. I will be starting their in August. When I was looking at schools I heard what was said about The Chicago School being a "degree mill" and flooding the market with new students who wouldn't be able to get internship placements, so I was a bit leery. When I visited the school, however, I was extremely impressed by the program and the internship match rates. They do accept a large number of students each year compared to other schools, but the class sizes are kept small. I was really interested by the fact that their core faculty are required to be practicing. Also, I just completed the writing assessment that all incoming students are required to do before or during the first semester. Depending on the score I get I might have to take an online academic writing "refresher" course. As tedious as that was, and might still be, I think it's a sign of the school's commitment to ensuring its students are adequately prepared. During the interview day the complaint that the current students put forward about the school was that the administration is too involved in their progress and that it begins to feel like hand-holding after a while, particularly when it comes to the dissertation. Everyone basically agreed that they were annoyed by that while it was going on, but once they finished the dissertation they recognized the value of the school helping them stay on track. Regardless of how you feel about that level of involvement on a personal level, I don't think that a school that was only interested in taking money and passing out degrees would spend the time and manpower necessary for that level of involvement.
There's clearly still a stigma attached to PsyD programs and an even greater one attached to professional schools, but so far everything I've learned about The Chicago School and everything I've heard from current students has persuaded me that they are a good school with a sincere interest in generating quality practitioners. Again, I can't speak about Alliant, but I know that they, like the Chicago School, are non-profit. The only experience with a for-profit school I have is with Argosy, and that only amounts to me trying to get information about them by filling out a request online and then being bombarded with daily calls from them for a period of months. They seemed a lot like telemarketers (not leaving voicemails, calling from different numbers) and I was really turned off. Part of the stigma associated with professional schools may be based primarily on the for-profit ones like Argosy.