Depends on the model, The 7200.10 line are quick but anything older than that is going to be slower than a Caviar of the same size. The 7200.8 line had some very bad batches, i think the 9 serries ran a bit warm but may be completely wrong on it.
Since the odds of a bad drive are so tiny i wouldn't worry about it. The warranty is a slightly different matter, where seagate have a notable lead (excepting the drives intended for industry).