Same as most everyone else, I haven't gotten my hands on any T gauge yet. I am hopeful, though.
Overall, the T scale effort seems to have been jump started pretty well.
The company did a great job getting details, trains, track, and structures on the market at the same time.
Right now the biggest issues are electrical pickup, poor eye sight, and fat fingers.
It's nearly impossible to get in the US right now, without a Japanese friend. Remember, though, in time; it will come.
Late in the developement phase, they added magnetic wheels to all pieces of rolling stock (powered or non) to increase power pickup. Sadly, it still isn't enough. Once you get that small, there just isn't anywhere to put much weight. (Rails were changed to steel, in conjunction with the magnetic wheels.)
On the up side-
I've read a report that a little time spent caring for these tiny mechanisms helps alleviate the herky jerky running. They still run lightning fast, but much smoother. I have personally wondered if rewiring the little guys with SMD capacitors might help. (2 units in each train are powered)
The motors inside these little critters are reported to be coreless 4mm in dia. That is absolutely phenomenal. Yet another kit-bashing/scratch-building door has been opened with these tiny motors. They run at 3 volts, yes, but that's nothing that can't be corrected with just a simple resistor in series. (If you want to get slightly more complex; a SMD voltage controller might work and allow better performance.)
Have you seen the details for this scale? They are higher quality than most mass-produced N/Z details. If you see a close up image and think to yourself "Wow, that's clunky and chunky. What were they thinking?"... Remember, this scale is TINY! The bicycles are barelly bigger than the date on a penny, and the pantographs - barelly bigger than the span of "In God We Trust". The vehicles, I haven't seen good photos of yet. I can't voice my opinion on them.
One of the better blogs on the subject:
1:450
-a few pictures on there showing a couple detail parts.
-Just my take. This scale isn't even in its infancy yet. It's still an embryo! Let it develope...