FlexRadio Systems is the new belle of the ball in amateur radio. These simple black boxes, festively adorned with a power button, an LED, a headphone jack, and a CW keyer port, are nothing to display prominently. They are controlled almost exclusively with software that you need to run on a Windows PC (more about that later).
Figure 1: The stunning good looks of the Flex 6300
I'm here to tell you they are magical. If you want to know why, I present the following evidence for your consideration:
Figure 2: The entire 40 meter amateur radio band, complete with actual jibber-jabber!
This is a view of the entire 40 meter band. The whole thing. At about 7pm (-7 GMT) you can see that the band is open. On the left you can see a pile-o-CW operators. On the right you see the sideband portion of the band, where I happen to be currently tuned. If I were pre-disposed to contesting  this would be a godsend. My radio, the FlexRadio 6300 can handle two of these such views (slices) to monitor and work separate bands at the same time. It even has a transverter output on it, just in case you lose your mind and want to get on VHF/UHF/Microwave for some reason.
Here are some issues I worked through:
- The software only works on Windows PCs, and it's a good idea to make sure you're running a beefy system. I run mine off of a Intel NUC 6i7KYK with a Razer Core external graphics card and a Radeon RX 580 and 32GB of ram. The on-board Intel video card could not keep up with what I wanted to do with it.
- The other platforms available are iPads and iPhones. This is awesome for operating from the hot tub, bedroom, or other places where you don't want to sit next to the radio.
- Make sure that your bios, and OS patches are up to date. A lot of problems were resolved for me by updating to the latest software.
- The Flex series requires an actual hard-wired network connection. You'll have fewer problems if you don't try to use the software over 100M, 1Gig networks just work better.
- Throw away the stock microphone. I wish Flex would just leave this out and knock the 75 cents off of the device. You can get a USB microphone for your PC that is reported to work very well. I use a Heil PR-781 (Yaesu adaptor cable) and I'm happy to report that I still can't make an SSB contact to save my life.
Overall I'm extremely happy with the setup. I don't get much use out of standard radio interfaces, so the PC software makes for very comfortable operating. It helps that my first contact was all the way to Japan on my 350' Horizontal Loop antenna on 40 meters.
I have several half-written Linux implementations of the SmartSDR interface, but it's a complicated enough task that I haven't had a chance to flesh it out completely.
 I'm not into contesting. I am happy to say that I made my first official entry into the RTTY-roundup sometime earlier this year. I made one contact. Mostly I was just testing the Ham Radio Deluxe program's multiple call-book feature.
 My HOA does not like antennas that are required by the FCC's concessions to the TV/Radio broadcasting industry.