After creating several forms in FormNX completely from scratch I fully agree with other reviews that this is the top tier form builder. It is very easy to use, and the interface is well laid and making sense, so despite lots of functionality available you won’t get overwhelmed, and creating simple functional form is just few clicks. But at the same time, all the advanced abilities seems to be included, so if you want fully customizable e-mails and thank you pages utilizing filled-in info, dynamic forms reacting to what the user fills in, self grading quizzes that show the user on the result page different info based on the score, self-prefilling fields by parameters from URL, etc., definitely give it a try. Also one important plus - when you delete submission with attached files, FormNX actually deletes these files (it may take several minutes, but it does) - in many other form builders this is not the case, so although you delete the submission, the files stay publicly available via the link forever.

The user interface is not 100 % polished, and I have noticed several problems regarding it (mostly minor ones, like the wrong alignment in some field, or inability to change something, because the field for the settings is missing), but the support is very fast and effective, and the problems are either already corrected, or the correction is promised. But that is only the stuff missed in the UI, the functionality is perfect and I haven't encountered single problem regarding it.

Several things that might be concern for someone:
- each upload field has limit 5 files and 20 MB. If the user places more files in the field, only first five is uploaded and rest is ignored. If the total size of the files in the field exceeds 20 MB, the form hangs after being sent and the submission is not saved, so it is wise to place in the title of the upload field something like (limit is 5 files and 20 MB in total). According the support, the limit will be raised in future.
- although you can set up almost everything else when designing forms, e-mails and thank you page, you can’t change color of the font (but interestingly you can highlight it with background color).
- FormNX doesn’t have it’s own SMTP server, so if you want e-mail functionality, you have to provide yours (Gmail etc. is OK).