They are both good kit.
I would probably go for the Agilent because of the experience of using Agilent's quite slick collect and return fixed price calibration service for several types of instruments like data-logger and spectrum analyzer.
Tektronix support may also be good, so you might seek more opinion from others who might be checking out this thread.
I know it is a bit lame to be swayed only by after sales support, but for most other features, they are both such very good equipment that the advantage for either is not so clear. You may like the DSP decoding advantage in the Agilent, but that may not count for much if you hardly ever use it.
Usually, if the specifications are closely competitive, and the reliability reputations are similar, then the lower price decides it.