A very recent development is http://www.readdle.com have updated their PDFExpert 2.0 app for the iPhone. I presume that this will also work on the iPad.
I have been tracking this for some time and this is the first app that is STARTING to handle forms - IMHO.
Now, PDF Expert will ONLY handle XFA Forms that are saved as Static PDF Forms in LiveCycle Designer. It cannot handle Dynamic XML Forms. However it does offer the facility to send the Dynamic XML Form to them and they will send you back a Static PDF version. I have not tested this.
Here is a Static XML Form in action (originally developed in LC Designer, but not very exciting):
PDF Expert also seems to handle AcroForms (originally developed in Acrobat):
Here the calculations in the AcroForm DO FIRE.
Importantly from the limited testing I have done, it appears that when the form is opened back in Acrobat on the computer, the data inputted in on the iPhone comes across okay.
Overall it is an improvement, but you would need to seriously stress test your forms on the iPhone/iPad before deployment. While calculations in the AcroForm did fire, scripting in the LC Designer Static PDF form did not fire.
If the form is simple and without script then it should work okay in PDF Expert. If it is more complex than that, I would give the iPhone/iPad a wide berth.
Now, having said all that, have you see Adobe's FormCentral (https://formscentral.acrobat.com/app.html). Using this online/cloud service you can create simple information gathering forms that are accessible from a computer AND via an iPhone and iPad.
Hope that helps,
I can't confirm.
My experience with PDF Expert is that it saves on the fly and allows the users certain set actions, like "send by email".
Maybe you should invest $9.99 and see if it works with your particular form.
I just purchased the PDF Expert app and you are correct that this newest version (4.2) does NOT support calculations in PDF Static forms created with Adobe Live Cycle Designer 8.0, regardless of what Static version you save to (6, 7 or 8). Yet, the static form work fine on a PC. Some buttons do not behave correctly, such as "reset" which would normally clear the form, and does so with some fields, but fills all checkboxes. Strange behavior and not the form I was looking for... of course, I lose 10 bucks, but that is the price we pay for trying a new app that does not have a "lite" version.
Maybe they will find a way to handle PDF fillable forms that make calculations based on choices made on the form.