OK, so an update after 2.5 years and ~21,000 miles:

This is still the best upgrade I've done to my 4R. The braking performance is SIGNIFICANTLY better than stock (2003 Limited 2WD). The truck sits outside 24/7 and I live in an area that gets lots of salt in the winter. They still perform perfectly. I usually lock up everyone's seat belts with their nose in the dash LOL, when I drive it after not having been in it a while because they stop so well compared to our other vehicles.

In fact, I noticed that the wife's 2004 GX470 was braking very poorly and I'm in the process of upgrading those to 5th Gen fronts. (Rear on GX470 is already the same as 5th gen 4R rears)

As far as the aforementioned hoses; I chose to use braided stainless on the fronts and just rubber on the rear set. Couldn't get RA to send the right Centric part number (inside the box was missing parts) after multiple tries, so went with the Delco from Amazon to finish the job.

So, yes it is worth it to upgrade.

Also, yes the rear rotor is just slightly too big for the hub, and I get a little click on occasion that doesn't affect performance. Parking brake works just fine. If I ever need to replace it in the future, I'll likely use a Gen4 rotor with the Gen5 caliper.