Get the Funtana, you won't be dissapointed. an O.S. 70 Surpass II is plenty for my machine. Almost unlimited verticle. Unfortunatly I'm on my second, a bad cell caused my Rx pack to fail in flight and lock the controls. I bought another the next day and was flying the day after. This time I mounted 2 packs on separate swithches. I swiched to a Saito 72 and am not as pleased with the performance. Go with the O.S or get an 80 or bigger for power.
Oh and by the way, the boss was never the wiser. From now on, when I crash an arf I'll purchase the same model for replacement and leave the box at the Hobby shop.