The only advantage to getting your podcasts from iTunes (on the computer) and syncing is that you can actually subscribe to podcasts on the computer. Each time you start iTunes it will look for new podcasts in you subscriptions and download them.
However, I will say that it's kind of spotty on this. If half a dozen podcasts have been added to your subscription since the last download, it may not get them all.
On the other hand, as long as you leave at least one podcast in the iPod app on the iPad (way too many pods an pads in that sentence), you can always tap the get more episodes button and be taken directly to that podcast in iTunes on the iPad.
Beats having to search for the podcast each time.