1- Forms are great
2- They offer many options of forms so you will for sure always find the one you need
3- They are very easy to implement
4- When you encounter a difficulty you can actually CHAT live with them and they are very responsive
5- Their forms can be very elaborate if you need them to be.
I have with them now for years (at least 5) and never been disappointed. Go for it!
1- Simple contact forms
2- Complex purchasing forms
3- Complex contact forms (doc uploads, multi answers..., several sheets with titles, ....)