the current SA hubs are still branded SA not sun tour or sun race (Sun Race bought sturmey archer).
2002-2008 they appear to have made a revised version of the ball-locking 5s 'sprinter' hub. 2009-2016 they made hubs with a (W) suffix, so X-RD5 (W) and X-RF5 (W). In about 2016 they launched the C50 series of 5s hubs which are larger and heavier than those that came before.
The (W) hubs use a different shifter from the sprinters and share almost no parts with them. They have a wider gear range but have several problem areas
1) the pretty alloy thumbshifter overhsifts and sticks on downshifts and this very commonly causes slippage in the hub. If this is not rectified the hub invariably breaks. You can cope with the usual duff shifter if you pull the lever back to the detent after every downshift. I have a scheme for rebuilding the shifters so they work properly, which appears to be 100% successful, but it isn't really a DIY proposition.
2) the bearings for the planet pinions are pretty hopeless; the planet pinions are solid and have spigots on each end, about 2mm long. These sit in holes in the planet cage and make the crudest, draggiest plain bearings imaginable, that wear out faster than is acceptable. it is bloody amazing that they have the never to make a hub like that; it is almost as if they have learned nothing from the past.
3) like most current SA hubs (and unlike older ones) there is no tab washer on the RH cone. This is required to prevent the RH cone from precessing inwards and destroying the hub. This commonly happens with both 3s and 5s hubs currently. You can fit a tab washer for pennies why they have omitted this vital part is a mystery to me.
4) There isn't enough grease inside the hubs
5) what grease there is, is not very good quality; I recommend something with solid lubricants and corrosion inhibitors, and more of it.
6) the (W) hub has exactly same actuator plate issues as current SA 3s hubs.
7) there are at least two springs that cause drag inside the W hub, all the time, and there is very little you can do about it.
8 ) the locking key assembly really needs threadlock on the small screw that holds the two halves together; without it the two halves can come apart and this results in a hub-smashingly terrible fault condition in which both suns try to be locked at the same time.
9) when the (W) internal breaks, I don't think there is another SA internal that goes into that hubshell, because it is a different depth to any other SA one. I have not yet found an easy way of making a 3s internal up that will go in a 5s (W) hubshell.
The shifting in the (W) hubs is pretty clunky (worse than in a ball-locking sprinter) especially 5-4 and 2-1 but improves once the hub is both run in and lubricated correctly. Most of these hubs break (usually due to a duff shifter) before they have a chance to wear out on the planet pinions.
But having said all that a (W) hub with a hub brake is a pretty useful hub on a utility bike; efficiency is fairly good in the middle gear so if you view it as 'a singlespeed with options' it will work pretty well. I've had one on my utility bike for a few years now, mostly in gear 3 with a load on. Without a load on I use gear 4 quite a lot and the extra drag is noticeable.
Whether the (W) hubs will continue to be available is open to question; they are mostly no longer listed on the SA website.
cheers