When I go running I don't have to lubricate the excess skin on my arms anymore. I did a race last weekend and thought, "wow, I don't have a bunch of flappy skin to deal with on this run, how nice!"
The main reason for the surgery was for long swims. The excess skin on my arms would rub raw when I swam more than 3-4 miles. This was very painful, particularly in salt water. I wish the river would warm up -- it's 42º now -- so I could test my new arms out. I have done several 6k pool workouts with no difficulty. At masters tonight I felt like I could swim forever.
Sometimes my left arm gets a weird bump along the scar line and my hands swell when I use my arms for long periods of time, for example on long drives. That's kind of disconcerting. But this is the only side effect I am still experiencing.
Here's the truth about brachioplasty: the recovery is really painful. And you end up with two huge scars that may fade but never go away. I didn't do this for aesthetic reasons. If a few months of suffering means a lifetime of happy swimming, that's an excellent trade.