I agree that auto bias is a good thing, I had very positive experience with the amps I owned.
As for tube testers, the B&K 707 or 747 are decent and can usually be had cheap at EBAY. Best of all they are transistor and need little or no calibration and won't drive you crazy with too many knobs to turn to get a reading.
Later, if you want a high end tester, the Hickok 752A is one of the best ever made but much more complicated.