I want to put a good word for iBal. I've been using it for about a year now and its the most useful app on my phone. I use it for every flight I make private and business and the time it takes to get results emailed for logging flight data is less than 20" which makes it very flight and user user friendly, especially when there's not much time before the flight (HEMS).
Also a good word on the developer Mike McCauley. I never met the guy but he is great. Every need I get about helicopter types makes its way into the app without hesitation. Excellent customer support, no doubt.
Bottom line, iBal to me is well worth the money
. To be honest I have yet to see a competitive app.
Cheers,
Jure