I have done this review a couple of times over the last four years and since there have been some new developments recently I thought I would do an update.
DNN "Forms" modules can be broken down into two groups: Forms modules (modules that excel or focus on the data input side), and web app modules or frameworks (modules that do data input and excel in data display).
We'll look at web app modules first:
In terms of sheer abilities Open Web Studio (OWS) still holds the crown. Unfortunately it also still holds the crown for the most difficult to use / learn. OWS is a mature module as it is built upon it's predecessor - ListX. A new development that could change the difficulty issue somewhat would be the video tutorials done by Paul Deschenes and available from DNNCreative. These are very nicely done tutorials and cover many of the abilities available in OWS. A major plus with this module is that it is open source.
In terms of ease of use combined with a high degree of abilities Xmod still reigns supreme. There isn't much you can't do easily in Xmod - especially when you combine the Fatgeorge Xmod add-on's to the package. Fatgeorge's File (Image) upload control is without a doubt the best in DNN, probably the best in asp.net, and could be the best on the net. Fatgeorge's Housekeeper add-on will (among other things) keep track of Xmod records that get deleted and then delete the files/images from your root folders that have been attached to the record. There are also many other add-on's available for Xmod - such as the calendar module that displays Xmod data in a calendar. The downside to Xmod is that it stores it's data as xml in a handful of tables. This means you cannot connect to other 3rd party tables easily. And it probably isn't the best choice if you are going to be working with very large data sets. But for solutions that don't have huge numbers of records and don't need heavy searching / sorting Xmod is quick, easy, and powerful.
XmodPro, from the developers of Xmod, is an alternative for those that need to connect to their own tables, need to work with large data sets, or need to do a lot of searching / sorting. It isn't quite as easy to use as Xmod and doesn't do as many things for you in the background. It is still a very new module, version 1.4 was just released a few days ago, and therefore doesn't have quite the abilities of OWS. Fatgeorge has a beta version of his file upload control now available for XmodPro - with basic abilities (auto thumbnail generation, file resizing, and a couple more). Look for this module to continue to add to it's abilities in the near future. XmodPro leans toward the OWS end of the spectrum with the freedom to build many things if you have the knowledge.
New to the arena is Dotnetmushroom's RAD module. I have only had my hands on this module for a couple of weeks but so far - WOW! For a version 1.0 release this module brings a lot to the table. This module stores it's data in regular sql like OWS and XmodPro. But it is more like Xmod in it's ease of use. It has a table builder built in. And it is much more powerful than most built in table builders. This is very handy if you don't have sql access on your server. It has button events somewhat similar to Dynamic Forms (discussed later). But the stars of the show are what they call the Navigator and the packaging abilities. Navigator makes it easy to build relational solutions and navigate between multiple RAD modules in your solution. This is somewhat similar to the old navigator module for ListX. The packaging abilities are very slick - it will auto create DNN tabs(pages) so you can package an entire solution and recreate it on another portal. OWS will do this too... but not by just clicking a few buttons. RAD also has easy to use calculation fields so you can do math. It has ecommerce abilities and some payment gateway features so you can build your own estore. I haven't played / looked at those abilities much yet so I'll have to save that for the next post. There are some things missing such as if/then/else logic, an easy way to connect to non-RAD tables (you can do it now just not point-and-click), and a couple of others. But for a 1.0 release this is very impressive. The Dotnetmushroom guys are already at work on version 1.2
Indoogrid is another module that can be added to this group. Indoogrid, as with many of the "forms" modules available for DNN, started life in a certain niche. Indoogrid's niche was just as the name implies - grids. And like many of the niche modules Indoogrid has expanded past that niche but you can still see it's origins in many parts of the module. Indoogrid and Enterprise Forms are the two modules on this list I don't own so my knowledge here is somewhat limited.
Forms Modules:
Dynamic Forms holds the crown for DNN forms modules. It is also originally a "niche" module with it's roots in quiz / testing. The latest release, 3.0 (now up to 3.1), added some impressive abilities to an already long list of abilities. The ability to auto create DNN child portals on form completion, the ability to create pdf's, a gridview feature to layout questions, etc. It has had fairly strong payment gateway features for a few releases now. The question events are a handy tool for input forms and testing solutions.
Enterprise Forms is a "niche" module with it's roots in workflow. If you have higher than normal workflow needs in your solution Enterprise Forms is still the best option.
The core Forms & Lists module, Helferlein Form, and Forms Master round out the forms modules for DNN.
Inbetween Modules:
SGSV (sqlgridselectedview) is a very good module for it's price ($10). It probably has the best search, sort, filter features of any of the modules on this list. Of course if you have the ability, and the time, you can build these features in OWS or XmodPro. It wouldn't take much for SGSV to be a web app contender - it's roots are in the display side of things so the input side is a little lite and it lacks logic features. SGSV is a very good choice for an easy to use module that will connect to your own tables inside and outside of the DNN database. With this module you need to create your own tables in the database.
Property Agent started out as a real estate module. It also has very nice search, sort, filter abilities. And the price is right here too. It is a good choice from an ease of use standpoint. It stores it's data in regular sql and creates the tables for your forms automatically.
Mash-Ups:
In the early days many people would mash-up Xmod and Listx. Today the mash-up of Dynamic Forms for the front end (data input) and OWS, XmodPro, SGSV, or Indoogrid for the data display is a pretty powerful combination. Dynamic Forms has tutorials on how to do this with OWS and Indoogrid on their website.
Some Add On Modules:
SQL Chart is a module you can obtain if you buy the $10 subscription to SGSV. This is a nice little chart module.
SQL Jobs is a nice module to have. You can use it to clean up after many of the sql based modules listed above. (If Mitch would ever update his Scheduled SQL Jobs module at Iowa Computer Guru's we could use that one! 
Just joking Mitch - we know you are busy and have contributed much to the community already!)
Netism Map Extreme is a very nice module that can integrate with most any of the modules listed here to display data from your forms in a map. Lot's of nice features such as Birdseye views.
If I have missed any modules or gotten something incorrect I'm sorry - please feel free to add to the thread.