In terms of model potential, Cycles 2 and 9 had the best cast.
I also may be in the minority, but I thought Cycle 7 had some great models.
You had girls like the twins/Melrose/Megg/AJ/even Eugena although she didn't perform well on the show.
The issue with Cycle 7 is that most of the girls had the looks and nothings else. A lot of them didn't even want to be models (Michelle), had no confidence or presence whatsoever (Anchal), or just couldn't take a good picture to save their lives (Jaeda/Eugena). But for the most part, I think the Cycle 7 girls looked like models with the exception of Brooke/Monique/Anchal.
But through it all, there were a few great diamonds like AJ/Melrose.
The weakest cycles were Cycles 4 and 5. Both had extremely unmodelesque girls and it's really no surprise that none of them have had much post-show work. In Cycle 5, there was really just Nicole and Nik, and everyone else sucked. In Cycle 4, the only girl who proved herself post-show to any sort of extent was Michelle. In addition, Cycle 5 had the shortest girls and the worst shoots.
I have always found Cycle 3 to be the most entertaining.