Basically, RDP and RWA use the same type of connection, something which was slightly different in 2003. SBS 2011 has what it is termed a RD Gateway or Remote Desktop Gateway over which both RDP or now RDC for Remote Desktop Client and RWA allow access from remote computers
In 2003 and 2008, the name was RWW for Remote Web Workplace. With each successive server, the functionality became greater. With RWA, the functionality is more than ever before. RDP is simply a small application which allows use to log in remotely to your client computers remotely or even from within your network. RDP connects over HTTPS (port 443) to allow an extremely secure connection. Probably the most secure you will fine. So, RDP allows one to connect to a computer desktop only. RWA, on the other hand, logs in using HTTPS and requires that port 443 and 987 (SharePoint -- which you don't need to have) are open. This is to ensure you can access the company web page, which is SharePoint.
There is a huge difference between RWA and RDP. Remote Web Access will bring you to a web page where each user can access the server or any client (they have permission to access) directly from the site. You can get to all of these things from London if you want. You don't have to worry if the computer you are using has RDC 6.1 installed, although it comes with Windows 7.
The functionality is incredible. First, you can access all computers. You can access your email (if using Exchange) using Outlook Web Access. For the first time, you can access shared folders including redirected folders, which is ultra cool. Again, unlike P2P, you as the admin, can decide what permissions to give out. For instance, you could have a folder just for you. To get to the screen with all of this access you first have to log in with the same username and password as the user has on the network. For this reason, you will want to always use very strong passwords. Never allow your staff to choose their own passwords or you will get Patsbrady1.
RWA is just as fast as RDP and just as secure. The only place where it is slower is the initial login.
You can use a non-public certificate but then anyone remoting into it will need a matching certificate and/or accept the risk (which won't be a risk). While you do get a free certificate from Microsoft, I would highly suggest you purchase a public certificate so you can use your exact domain name and remote computers will bypass the certificate checkpoint. So, say your domain is Astoria.com. Then all you would need to do to access RWA would be to open a browser and type
https://remote.astoria.com (if it uses the same login verbiage. They seem to change it every time. For me, it is
https://domain_name/remote.So, at home you could make a shortcut to
https://remote.astoria.com. Clicking on it would bring you directly to web access.
The really cool thing about using a static IP (although I believe there is a workaround) and a certificate is that while you can access your web mail and SharePoint from RWA, you could also have three URLs on your desktop:
https://domain_name/remote for RWW/RWA, /owa for Outlook Web Access and :987 for SharePoint. Note the colon instead of the /forward slash due to its being a port. I simply click on any of these to get to my desired destination. Right below them I have RDC just to show you how close they are.
Now OWA and SharePoint wouldn't apply to you since you don't have them and, even if you did, they would be in the cloud anyway.
Two excellent resources for this stuff are:
Windows Small Business Server from TechNet
and
Susan Bradley's blog (she is considered the SBS Diva)
Sorry this is so long, but as you can tell, Sandeep and I are very passionate about SBS. After you cut your teeth with Essentials and you move to what will then be SBS 2013, including Exchange and SharePoint along with a non-SBS server, you will see why SBS is the best deal Microsoft ever came up with.
So, essentially, they can both allow access to your computers via RD Gateway, but RWA will allow your users a lot more options without your having to remote to their homes to set up RDC.
PS Since I haven't set up RWA yet either (I am on a VM and haven't set up my network yet) I had to steal a few tips from
TechNet PS: Your users can customize RWA, moving things around and adding/subtracting certain features. And, if you are worried about a particular employee you can, that's right, go to the server and take away their privileges. This can be done per computer or every computer.
