I bought a 2012 Timber Ridge 240rks at the start of last season and am quite pleased with it. It seems to hold up to lots of road miles better than any other TT I've owned. Last year we drug it from the SLC Utah area to the North Rim, Mesa Verde, Durango CO, Flaming Gorge, Yellowstone, Yosemite, The Redwoods and coastal hwy etc. About 8.5k miles of road tripping total. We've also experienced temperatures from the teens to 110F range without any issues, and the insulation seems quite acceptable. About the only thing I've done to it is replace most of the light bulbs with LED's since we mostly dry camp, otherwise it seems to have come equiped just right.
As for maintenance, We had a few vibration related issues like the vent knob screws vibrating out and the knobs falling off, a couple screws under the sink worked loose and needed tightened. I had a leaking line on the water heater I had to tighten, and the TV quit on a long trip when we were taking the grandkids (Only time since we've had the TT we really wanted the TV) They replaced the TV without any issues so I have to say my limited customer service is good.