My macbook air struggles to play videos from the comedy central website. I too wonder if the iPad can handle such a seemingly simple task? My ISP is pretty decent, but the MBA really struggles, even when all other programs are shut down...even after a restart, the video begins to lag! Guess the instore comparison is a good idea!
To be fair, my desktop at home and my brother's desktop, both decent machines, struggle to play videos on the comedy central site. I think the iPad would do a better job of this, only because of how many apps there are that specifically handle Comedy Central shows...
To the OP, my only thoughts on this issue is that the processing power doesn't matter that much when comparing these two devices. Honestly, even if the MBA has less processing power, I'd wager you could still do more with it because of the OS. Although, with the way iOS is evolving, that may not be entirely true in a couple of months or so... I'd personally not recommend a spec comparison between these devices to determine how useful they are. There's a lot more than just the bare bones specs that come into play here, mainly functionality and usability.
Are you going to encode a video on your iPad, no. 
