Nick,
If you can find it, use the LGB Oil pen for rolling stock and their Gear grease for plastic gears.
As for the comment about detail, what about the Aristo Mallet? I have yet to see anyone post that its detail was lacking. Paint on the drivers, yes. Details omitted or simplified? Not that I am aware.
Its not a fair comparision to look at new steam releases versus the Aristo 4-6-2, 2-8-2, 0-4-0, 2-4-2, all of which were designed prior to 1993. OK, the mikado didn't show up until 2003, but it is essentially the exact same mold as the Pacifc. If you look at locomotives of that vintage, I think you will find that the Aristo stuff was on par with the LGB, and better than the Kalamazoo, and some of the Delton stuff. Certainly, it was better than the Lionel Atlantic. Things have changed a lot in the detail department in the last 5 years of large scale. Aristo is really responsible for making this stuff affordable. Before them, the market was LGB (and they had higher prices for their trains than they do now) controlled. USA was making those wood reefers and boxcars, identical to LGB's. It wasn't until after Aristo started to gain some ground with their FA, U25B, RS-3, and 4-6-2 that USA got in to the locomotive and freight car 1/29 business.
How did you feel the 0-6-0T compared to either of your NYC Hudsons or the AML K-4 Pacific? In my opinion, it looks like they forgot to do the detail work on the wheels and running gear. The running gear and wheels on both the USA Hudson and the AML K4 look great. Very realistic. Also, I didn't care for the shininess of the main and connecting rods. Something about the running gear and wheels makes it look cheesy. Maybe it will pull well on your RR, but I have no intentions of owning one.
Mark