Great tracker. I recommend skro all day. Best Price/quality relation on the market. Have to admit it as some things to polish like data loading specifically (for me) but overall great. Also I thing this is the best tracker if you'r just starting out, the way you can "see" the traffic slices helps you A LOT to understand the game.
I recently switched from BeMob to Skro and I'm glad I did. I'm absolutely loving Skro so far. The interface is intuitive, easy-to-use, and has all the features that you expect in a good tracker, plus some. I also love that the pro account doesn't limit you on the number of landing pages, campaigns, traffic sources, and offers as BeMob does and it's $10 less per month! Also, the support has been amazing. It's fast and thorough. I don't think I've waited more than 10 minutes to get a question answered.
Skro is one of my favorite new trackers on the market. They have done a GREAT job over the past year improving their tool and the addition of free PropellerAds integration (cost tracking and optimization) makes this a 5 star option!