I'm what you'd call a ClassPass superuser; on average, I go to about eight or nine classes per week. Some of what are considered the more challenging fitness studios are in my regular rotation. The 30 minute FUBAR Versaclimber class is my most dreaded 30 minutes of the week. I'll be upfront: it's not fun, but it's effective. The proprietor, Jacques (and Jens, the other instructor I had) trains elite athletes, and that mentality is reflected in the workout. First and foremost, he is about results. Efficient, friendly and encouraging, he pushes you to break through what you believe your best is - and he would know how to do that as a quick Google search reveals that he's a world record holder in several Versaclimber categories.
The facility is very spacious, modern, and clean. Street parking can be a little bit of a problem, but the Westside Pavilion is about a five minute walk and there's ample free parking there. If you're someone who is about results, I highly recommend Sirens and Titans Fitness.