We don't post on forums lately as much as we have at times in the past, but I recently noticed a thread where we are somewhat uniquely qualified to comment. By the time I'd finished my response, a fully formed blog post was on my hands. The original forum thread is here.
I can only speak at great knowledge with regard to T11s versus Novatec F482SB, but there are several meaningful differences.
First, the titanium cassette body as many have mentioned. I've seen 3 year old ti cassette bodies that were less chewed up than 3 ride old aluminum cassette bodies. This sacrifices a few grams and adds significant cost. The grams are meaningless in my opinion but the dollars are real.
The T11 uses a steel axle as opposed to an aluminum axle on most other hubs and certainly the majority of lightweight OEM hubs. This costs a few grams again, but is an area where we have seen a meaningful difference in longevity. We've seen a number of bent Novatec axles. Far from an epidemic or something that's going to happen to everyone, but I wouldn't recommend them for cross use, or heavier riders, or people who like to take road bikes where road bikes aren't necessarily meant to go. A lot of times people with lightweight hubs wonder why the hub won't hold a bearing after a while, and a bent axle is usually the culprit.
Both use steel pawls and drive rings, but the T11 drive ring gives some points of engagement back in order to have deeper engagement. You very occasionally hear about skipping engagement with Novatecs but in some other hubs it's more of a thing. In my opinion, unless you are Hans "No Way" Rey, speed of engagement is something you will never notice in a million years but a skipped engagement could have an acute bad outcome.
Overall bearing spread on the T11 is quite a bit wider than on any lightweight OEM hub I've seen. The T11's hub shell bearing width is maximized, and same with the bearings inside the cassette body. We have bench tested stiffness of various builds with various hubs, and the T11 always comes out at the head of the class. The stiffness difference between a wheel built with a T11 rear and an F482 rear is usually on the order of one spoke group (i.e. a 24h wheel with T11 is stiffness equivalent to a 28h wheel with an F482). How much of that is down to bearing spread versus axle differences or other factors I have no way of isolating and thus I can't say.
The bearings on F482s and most OEM hubs are open spec, meaning that different places will be selling "the same" hub with different bearings. We always used EZO ABEC 5 bearings in the Novatecs we sold. I've heard of Novatecs gaining a reputation as being a dry weather hub, but that hasn't necessarily been our experience. I'm inclined to say that there are hubs out there with lesser bearings causing that impression. In any case, all T11s come with Enduro-made ABEC 5 bearings.
Tension balance on either is about as good as you can do with 11 speed hubs without going to a radial drive side (and that didn't work out so hot), and in our deep experience this is a non-issue.
On the front hubs, T11 front flange and bearing spacing is much wider than a Novatec A291's. An A291's flanges nest inside of a T11 front hub's flanges, and the T11 has higher flanges. The stiffness increase between otherwise equivalent builds is noticeable there.
As far as ease of service goes, both are dead simple but the T11 is actually easier. Undo three 2mm set screws and you can take the thing all the way apart. An F482 is hardly complex, but requires two 5mm and one 10mm hex. T11 front requires undoing the same 2mm set screws, while the A291 front requires two 5mm hexes. Both are WELL within the capability of anyone with greater mechanical aptitude than my brother (which is about 99.6% of all people over the age of 4).
Cost differences are significant, and that can't be ignored.
For full disclosure, we have built and sold many hundred (I don't know exactly how many of each without doing a research project) of each hub I describe. We currently sell T11s but do not currently sell Novatec or any other OEM hubs. Fairwheel had a stake in the SL23 project and in my opinion treated the Kinlin/SL23 comparison fairly. Wheelbuilder.org was created by Zen Wheels and, so far as I could ever tell, he was the sole contributor and not very transparent about it (the royal "we" being just one example of that). November is imminently launching a hub produced by White Industries that is very closely based on the T11, which is undeniably related to our good opinion of White Industries and their products, but our good opinion of White Industries and their products is what led us to seek this cooperation with them in the first place. This hub set will address the cost difference between T11s and OEM hubs.