I like them, what I don't like is that (since they are all Standard cars) PD doesn't seem to have tweaked their center of gravity since GT4, from what I tested. Some of them are unrealistically hard to roll over. Look at this image, for example (sorry for the size):
After many attempts in rolling over this Daihatsu Move, one would expect that the car, since it's quite tall (over 170 cm in height) would rest on the window side, but instead it keeps trying rebalancing itself to the upright position, and in this photo you can see it resting on its wheels (although it's supposed to be a top heavy vehicle), actually just because there was the fence there preventing it from going back to its original position.
This vehicle too (Honda Life Step Van, here in a custom black paintjob. Too bad that wheels can't be changed on standard cars), another quite narrow and tall
standard kei car, behaves the same: essentially almost impossible to roll over, when you think it's about to manage that, the car seems to try hard rebalancing it self in its upright position:

(click for a full size version)
Did anybody else experience this odd behavior with their cheap, tall and narrow slug cars?
Still, I like them, and actually several of them because of their low weight when fully tuned are quite capable of being competitive despite their low power. In general I find them more fun to drive than bigger, faster cars.
I enjoy flogging the '83 Ballade Sports CR-X around Autumn Ring Mini. That seems to be my haven for slow, light cars.
Yes, Autumn Ring Mini and Tsukuba seem the only places where slow, light cars are quite fun to drive.
Too bad there aren't many other similar small tracks for them.