I think that if one team would liketo use it, then it should be in play. If the other team choses not to use it, well that's their choice.
I think that players do abuse the DRS a little bit, like for ones that just pitch outside, or just go over the top. I think there should be a 5 second time limit, as you know straight away whether you've hit it or not, and whether you think the batsmen is out. None of this 15 seconds, where they meet in the middle and discuss it before deciding to review on the off chance you may just be not out (batsmen)/or it may be out(bowler).