I quite like SA hubs because they are usually made well enough and you can buy spares for them. However with a few models one or both of these things does not apply. The SA 'dual drive-esque' hubs (CS-RF3 and CS-RK3 etc) seem to lack spare parts backup; leastways you can buy a spare internal but other parts specific to this hub don't seem to be readily available.
Inside it is about as simple and as well made as the current AW hub but the high gear drive to the planet cage is via 'plunger pawls' which can stop plunging if there are tiny (by SA hub standards) particles in the grease. If the drive slips in third gear the pockets the plungers go into tend to get chipped and this makes more particles, and..... well you get the picture.
If you decide to nip this in bud by cleaning the internal, bad news; the plunger pawls cannot be removed for cleaning, which means that you can never be quite sure that you have removed all the particles in the spring pockets which might jam the plungers again.
There is also a small issue regarding the running clearance of the internal. Traditionally the running clearance in SA hub internals is adjustable ( screw the RH cone home and then back it out half a turn) but in CS-RF3 etc the RH cone is screwed home and if the running clearance is too much, tough, you can't adjust it, not without machining parts anyway. If the clearance is too much and there isn't enough grease in it then the hub can get a bit rattly. CS-RF3 etc use a longer cable pull than normal, so that you can control the hub using a MTB front shifter if you want. What you cannot definitely do is use a standard SA 3s shifter.
If the CS-RF3 suffers major blow-up on the road then I would say you have a fair chance of making it work again (in the middle gear at least) provided you can fit new high gear drive pawls (same parts as AW I think) and removing the planet gears if necessary. [edit; thinking about this, I'm not sure this is readily possible in fact; the planet gears are permanently fixed into the planet gear assembly and if this is omitted, the ring gear is no longer located properly, meaning that you will lose drive in all gears. Parts pdf here
http://www.sturmey-archer.com/files/catalog/files/300/PART%20LIST%20-%20CS-RF3%20CS-RK3.pdf ].
So in the short run there isn't that much to choose between the Dual drive and the CS-RF3/RK3 etc.; neither design is perfect. In the long run I think the SA hub is a better bet simply because you will be able to buy some spare parts for it rather than virtually none.
cheers