The difference between the MBA and the MBP really isnt that big in terms of weight. Its like ~700g or near enough?
If this is your only computer then you are much better off with your MBP. The small difference in weight isnt worth the big difference in power if you don't have another machine.
The weight may be similar, but after using my MBA that is about the height of a MP keyboard, the MBP feels like a beast with its giant lip. Not nearly as comfortable to use.