Update - first impressions using TaxAct:
It has generally been OK to use, but a little discomforting that it directs you towards very specific US forms etc (as you might expect) where it is not obvious how at times to enter your non-US info. I struggled on this with Schedule A to enter my UK bank interest received.
It has also automatically calculated things which are not applicable and I need to change but cannot do this. For example, my wife is self-employed so I fill out Schedule C. This was fine, but then it calculates her social security tax owed, however due to her paying UK SS equivalent, there is an agreement in place which makes her exempt from paying this. However I cannot see that option on the software itself. It has also added the "Qualified Business Tax relief" which I wouldn't normally add, because of foreign self-employment, etc along with the previous point.
Also, it is unclear if I can upload and add a supportive schedule/cover letter explaining things like foreign tax carryover calculations, exchange rates used, etc.
Finally, if you want to talk about these "tax issues" to a Tax expert, then it looks as though you need a US phone number, which I don't have. I'd actually prefer to be able to ring them up to discuss but the only number seems for technical/software issues which I am not sure is going to get me anywhere.
Anyone with any prior experience on any of these nuanced issues? Also, can you e-file using "Free-file fillable forms"? Or is that paper only? Thanks in advance!
PS - can you put a bank account for the refund payment that is not in your own name? E.g. if I wanted the refund to go to a relative's US bank account and they can transfer me the money separately, rather than wait for a physical cheque?