My family had a similar reaction to Transformers at USF. We wanted to like this ride but ...
On the upside, let me start by offering that my DW loved the look of the large square building. I know several have questioned it but she thought it was great thematically with a "studio" where sightlines only matter depending on filming angles. She also really liked the gigantic Transformer above the entrance and the Transformers meet & greet, though both looked really impressive as "actual" Transformers.
On the downside, everyone in my party (DW, our 4 teenagers, and 3 teenage rookies traveling with us) thought Spiderman was better. Transformers is longer (we all thought) but Spiderman was a more cohesive story. Spiderman offered more variety in its various viewing screens whereas every Transformers viewing screen felt like they were showing the same thing; some "good" Transformer fighting with some "bad" Transformer. If we knew the characters better we might of appreciated it more but, frankly, one Transformer looks pretty much the same as the next whereas Spiderman villains offer variety. For the 9 of us, all thought the old Spiderman was still better.
BTW, Diagon Alley looks like it's going to be huge.