Over the past 10 years I have worked on a multitude of routers / firewalls.  SonicWall is my absolute favorite.  In operating systems, I have switched around liking one over the other but in firewalls, SonicWall has always been my champion.  

One of the best features is you do not have to be a genius to program the firewall.  No memorizing long commands and perfect syntax to be used in command line.  There is a simple, easy to understand GUI that is web based.  Any computer with IE or Firefox (no chrome support, yet) can connect and make changes.

The price is just awesome as well.  We have had customers request Cisco and I throw in a SonicWall quote to compare; SonicWall wins hands down every time.  The add-ons that people crave like Intrusion Protection Service, Antivirus / Anitspyware protection, and Content Filtering are very solid products with low prices.  

Wireless: SonicWall has you covered.  My first sonicwall wireless install was for a 3 story 15,000 square foot office building.  I placed the access point dead center vertically and horizontally and I had the whole office covered.  Not one single dead zone.  This was in 2005.  Pretty much unheard of to cover that much area for about $500.  Recently we installed a much smaller office with 4 access points, let's just say the neighboring tenants are now having trouble using their wireless because the SonicWalls are broadcasting so well.  

The two things that just bring it home for me are support and reliability.  When I call support, I do not wait that long and I get knowledgeable people.  This is not like calling a PC company and everyone reads a script.  In the reliability department, I have installed hundreds of these units and the most common replaced part, power adapters.  In 10 years, I have sent 1 SonicWall back to the manufacturer for replacement.  

Everyone's blood is blue until it hits oxygen, mine just happens to be SonicWall blue.