@OP. From personal experience, Passlabs products are extremely reliable.
As Dynamiclinearity says above, the number in the amps' name is the Class A power output.
Hi-Fi News magazine has just reviewed the 30.8. The concluding line is "It's a performance that should put a smile on the face of all audiophiles, bar those obsessed with 'clinical neutrality', and for a sane price."
Paul Miller measured the following dynamic power outputs into 8, 4, 2, and 1 amp loads: 105w, 205w, 357w, and 470w. That's on a 230V mains. Pass power amps sound a lot more powerful than they rate nominally, because they are a lot more powerful.
Dynamic power measurements aside, I've never heard any change in character in my 60.8s when driven hard, albeit in a small room where I don't need massive volume levels and I doubt the amps ever stray outside of their Class A power output.