I have tried about a dozen different Ballistics Calculators. I have a Windows SmartPhone so my options were pretty limited, since most people are NOT supporting Windows Mobile. IF I had reviewed this the first week or two that I had it I might have given it a LOW WARING. However, I have now been using it for about a month, and I find it does EVERYTHING we shooters need. It does have a bit of a learning curve and the HELPS are not very good, and/or hard to locate. It is not pretty or fancy, no GUI (Graphics User Interface), only text BUT when it does what you NEED who cares. I like it looking nice, if possible but it does not make it work any better. I have compared this program with other mobile B.C's (Ballistic Calculators) both mobile and online and I find myself returning to this one over and over. I have decided to make THIS ONE my primary B.C. That should say something. I am a retired Police Officer and sniper, so I do know a little about what I am talking about. Just yesterday I compared it with some very good ONLINE B.C's that I had printed out the charts that they produced, using the EXACT same settings, (bullet, weather, etc.) and for the most part BallCalc had the EXACT or almost exact same Tables for drop, wind, etc. But this one is MOBILE, so I can change settings in the field, like temp, wind, altitude, etc. I have a wind/temp meter, and an GPS with good elevation so I can know what the exact conditions ARE when I am shooting. So I would HIGHLY recommend BallCalc, and it if FREE, what more could you want?