I don't ordinarily make recommendations anymore. One reason for this is I felt really burned when i recommended JustHost a few years ago, and my site was hacked. I asked them not to renew, spent countless hours on the phone, and they still have me listed and charging me for something i told them i did not want. So not only did they not bother helping me, but continue to cause me more grief. They are the worst host ever. So i removed them from my recommendation list, and eventually threw out all my recommendations. But I feel good about the following two recommendations, and although they are pricey, they are worth the cost.
Firstly I won't recommend something that hasn't been through the ringer with me, their tech support, their forum, and their problem solving ability. Those the the fundamental qualities you should look for in a good product or a good service.
For WordPress Forms, I now exclusively use Gravity Forms.
I formerly used some of the free forms available on WordPress.org, but no longer. Gravity Forms has everything listed above, and a whole lot more. I've been able to create registration forms, paypal connection forms from the plugin. You can program the forms for conditional elements, so for example if you are collecting an address from the form, and you have some dependent questions based on their answer, you can hide or add other elements to the form following that element. And you can program the form to show previously obtained information to solve the problem of their having to answer the same question over again. I don't believe any form found on WordPress.org will do those things easily, and again with the qualities listed above - technical support either through a very active forum or their staff members.
The other recommendation I have is for Backup Buddy, from Ithemes.com. This plugin does an amazing job, and again it is constantly improving. They have a dedicated support staff, a lively forum, and do a very decent job of fielding all the sorts of questions arising from its use.
I incorporate both of these things in sites where I have a professional need of their use, and rely on them heavily. When I develop a site using WordPress, and have a maintenance agreement, my clients get both of these plugins. The maintenance agreement allows me to update the plugins on a regular basis, and keep their registration current.
For sites that I develop and clients decline the maintenance agreement they have the plugin but won't be able to update the plugin to the latest version, and their registration will eventually lapse.
In other words its the cost of the plugins that are pay forwarded for the use of the plugins. They will continue to be used in the site, will still function, but there is no guarantee that the next major revision of WordPress will work with the lapsed version of the plugin. So everything has to be kept up to date.
That's why I think the maintenance agreement is important. For security, compatibility, and peace of mind.
Update: I no longer use ithemes for backing up. Currently i am using updraft plus + aws. I continue to use GF and always recommend siteground.com for hosting.