Sirs,
A little over a year ago I decided to move away from having a separate PDA and phone and purchase a device that would combine those functions. I wanted a device that would access the internet and it had to be compatible with the APDL. As an airline pilot I've no desire to go back to manual logbook entries. Ultimately I settled on the AT&T Tilt and the experience has been less wonderful. The initial APDL version I installed was less capable that what I'd been using on my Palm (not importing trips into my calendar) and crashed frequently. It was so unstable that I began saving the log page every time before closing APDL. Installing version 6.1.4.0 solved a lot of those issues but I'm still suffering from Active sync problems. The monthly process of importing my schedule generally requires multiple swaps between the three USB ports on my laptop to get a solid connection and import the schedule file. I've also found the battery life on the Tilt to be generally very poor, (It must be charged daily and using the GPS quickly kills the battery) the mobile version of windows explorer simply sucks when compared to an IPhone and the screen is very hard to read in direct sunlight.
I have a little over a year to go until I can replace my phone and right now I expect that when that time comes I'll be getting a new IPhone. I've several friends and family members that have acquired them and from what I've seen it’s a vastly superior device to my Tilt.
I use my phone/PDA for a number of functions and while APDL is an important one its just one function. Looking at what the guys I fly with have in their hands I've noticed that the Iphone is quickly becoming the phone dejure amongst my peers.
I mention all this because If I were in your shoes I'd be reconsidering my software development priorities. I don't know what your customer base looks like but I'd bet that the majority of us are professional pilots. As such a new version of Logbook Pro no matter how wonderful isn't going to be as desirable as a version of APDL for the Iphone. To my way of thinking you can't get it to market fast enough.