Roller Rocker Arms durability question

[mikep]

I'm probably going to buy myself some roller rockers for christmas. Ive used them before but Ive heard that the aluminum needle bearing rockers will work harden over time and will crack although its not a problem Ive ever seen manifest itself. I'm tending to think this is a problem more with cams that use very high tension valve springs. Mine are the typical .550 lift Z28 springs that world product supplies with their SR heads. As My lift is more in the .440 range I dont think it would really create a problem although going with 1.6 rockers is a possibility I have looked at . Only thing I dont like about the 1.6 rockers is that I would probably want to use these rockers with a different cam in the future and while this cam is on the mild side I dont want to go overboard on valve lift . I have screw in studs and guide plates so pushrod clearance isnt an issue. Lot of rambling there but has anyone here ever had a real problem using aluminum needle bearing roller rockers on the street for extended periods?