I bought a Takara Kabuto (a Kent product, I believe) at a thrift store a couple of weeks ago. The black paint had some scuffs, and the yellow Kenda tires had faded almost to white, but it was straight, except for a ding in the alloy front rim. I installed a pair of wheels from a Sole single-speed, adjusted the brakes and lubed the chain.

I rode it twice this past weekend, for a total of 45 miles. It's not that bad. I think a lot of the problems that people write about on Amazon, etc are due to assembly errors. The Takara frame is high-tensile steel, but the tig-welds are really excellent. One feature I like very much is the longer chainstays, which allow the wheel to be further away from the seatpost, making this less like a track bike and more like a relaxed touring bike. The crankset, seatpost, stem and handlebars are steel, so not lightweight, but durable, and easy to upgrade as time and funds allow. The wheel rims that came with it were decent alloy on nice alloy hubs. I'll likely relace them with new rims so I can have the option of wider tires. Stock tires are Kenda 700 x 35 with a sort of universal tread, max pressure 85 psi. The wheels I installed from the Sole also have Kenda tires, but they are a different model, a semi-slick 700 x 25 that can take 110 psi. Pumped up to a conservative 90 psi, the bike still rolls very well, gliding along with almost no effort.
The sidepull brakes are alloy and work ok, but the pads could be grippier (maybe they were grippier when the bike was new, but the rubber seems to have hardened). The brake levers are alloy in plastic hoods, with cables routed under the bar tape. I didn't find them uncomfortable. This is the first drop bars I've owned in a long time, and I'd forgotten how nice it is to be able to change hand position.

The stock saddle surprised me by being reasonably comfortable, although you'll never mistake it for a Brooks. I rode for an hour before stopping for water, and it wasn't bothering me. Really, the worst aspect of the bike was the original heavy tires, and those could even be appropriate if you were going to ride on gravel. For pavement, I'd recommend replacing them with something slicker and narrower, a 28mm width would probably work with the stock rims and be a nice compromise between speed and comfort.

I read some of the reviews on Amazon before I bought it (it was at the thrift store for a couple of weeks, not many people buying bicycles in January) so I didn't have great expectations going in. However the Takara surprised me by being quite a bit better than I expected. If the front rim hadn't been dinged, I might not have even changed the tires. But changing the tires did make a very noticeable improvement, so I'd recommend that as your first upgrade. The advertised weight is 29.5 lbs, and if you replaced all the steel components with alloy, you could probably get it down to 25 lbs.