I flew with a PCAS unit (XRX) this afternoon, it was its first use by me. I was surprised by how many (non urgent) alerts it warned me of. On my flight to LFAT it was generally quiet once I was above FL55, East of SFD, but nearer Shoreham (returning), below FL45, on my return, it was almost constantly showing other traffic, usually within 1000' vertical and less than 3nm range. Of some concern was that I only spotted two of these visually, these were about where it "said." It must have warned of about 20 - 30 ones which I didn't see, either because I couldn't or did not have time to concentrate on looking for them,
I was squawking mode "S" throughout.
Rich