I can't speak from experience but from judging by logs (and my own exp w/ ArA) I'd say results seem pretty similar.
Though I have seen people report 5lb gain in LBM off a 4weeker of 25mg osta. I'd be very cautious where you purchase osta if you decide on that. Research companies don't always sell what they say they are. And also be cautious of estrogen-related sides. Saw a few people report about sensitive nips. I'd go for Celtic Labs Ostabol, just because they carry quality product (and it's also in pill form/more convenient)
Again though, I don't have any experience with ostarine so my opinion on it may not be worth anything, but I can say I've ran ArA a few times (3 or 4) and it's good ****. Interested in what people think of stacking the two..