Is the iOS 6.1 update on iPhone 3 safe to update?

On my first iPhone there were problems, and the update didn't help it wiped out everything and among other things had to get a new iPhone. The iPhone I have now works, so should I risk this update? It's a 3GS.

Yea it should take the update. If not tell them all the problems you had if it does fail and the previous phone and they should give you your money back.

1st off there's no iPhone 3 (at least you corrected yourself in the end & stated it was a 3GS)
2ndly, there's no iOS 6.1. I think you mistook it for iOS 6.0.1
& to answer, I don't see any reason why not to update. As far as it "wiping out everything" just do a backup before & restore from that backup after.

I've updated my original iPhone from 2.0 to 3.1.3, my iPhone 4 from 4.0 to 6.0 & now my iPhone 5 from 6.0 to 6.0.1 & still have data from that original iPhone on 2.0 because of that.