Never screened with an agency before, I've only seen indies in the past.  
Does it take a while for them too properly screen? Not sure what to expect.

The indies you have seen don't do screenings?

They do but I'm on 411 so its generally very easy through the site.

Great agency, screening process was painless and pretty much comparable to screening I've gone through with indies. Their girls are also great - relaxed, beautiful, and fun. I highly doubt you'll be disappointed if you choose to use them.