I used Bemob a lot because their support is top notch. They will help you setup your postback URL of your traffic source from scratch. I learned a lot from them by asking questions through their support chat. Another thing that made me use them is the discount for 3 months. I got 3 months 25% discount from them twice. All I do is ask them if it's possible to get a discount. The support gets back to me with a discount after coordinating with the finance department. I highly recommend Bemob to someone who's looking for a tracker..