The only thing I have found them useful for is on siding jobs....my grandfather used one all the time in his woodshop, and the attachments Craftsman used to put out made them versatile...but like any saw, they can be very dangerous. The new one we have was bought because my buddy Bill wanted it...and all it does is gather dust and square boards from the mill.
I will get one of the old Dewalts some day...a 12 or 14 inch saw, simply because they have great capacity....a 12 inch saw will cut 16 inches, and a 14 will do nearly 18...they have a place, but there are far safer ways to do anything they do, except crosscutting. Of course, if they come out with a SCMS with 20 inches or so capacity, that will be the end of the radial arm saw, IMO.