Shiho's voice threw me off, I thought it would be a little deeper, even somewhat like Yori's voice. It will take some getting used to for me. I was also a bit skeptical about Aki's voice at first but now it sounds "just like Aki" to me, if that makes sense. Also, I thought it was Mari at first when Shiho spoke in her scene, before appearing on the frame.
Momoka's voice suits her well though.
EP4 was much better animation-wise, only the scene where the SS Girls were playing was done... in a questinable way. Shiho also looked a little strange to me once she picked up her phone, but I can live with that. Also, I don't know if it was it just me, but the BGM felt a little too loud in the scene where YoriHima are at the rooftop near the start, and Himari almost says she "loves" Yori.
I actually forgot that Shiho appears this early, it was in the Vol.2 Extra. I thought she only made a physical appearance on Chapter 15.