Okay to start with, this gun is cheap. But, being cheap is what makes it great. It's easy to come by. Easy to buy. Easy to work on. Easy to make into something fun. Because I like lists, I'll start with some pros and cons.
Replacement parts are abundant and inexpensive
You can count on having to rebuild even a new one
No scope rail
No safety (I can't even count the anti-bear trap)
You can find these guns all day long for $5~20 in shoddy (aka “New”) condition. A cleaned and tuned piece that's working properly you can get for $50. One with a properly trimmed stock and welded on scope rail...less than $100. Cleaning one of these guns is a matter of removing two stock bolts and only a few pins. It can be done without a spring compressor, too, though I really really really advise against that. Thanks to the mystery-wood stock and the mechanical simplicity, the gun only weighs about 6 pounds. The internet in general says more, but the three I have in my possession only register a hair over 6lbs. Lastly, Pyramid Air supplies a rebuild kit for about $10..if it's even required.
The stock is my biggest complaint and the first thing to go on all my examples. They are terribly shaped. The grip is about the diameter of the big end of a little league baseball bat, and about as comfortable to hold while shooting. There is a man in Alaska who cannot scratch his head during the month of September for fear of being mistaken as a moose and, consequently, shot. Maybe he can comfortably grip the TS45. I cannot. The stock is also quite short. About to the degree of a Red Ryder youth gun. It's tolerable for me, but only briefly.
Lesser complaints are about the mechanics of the gun...which really aren't bad. The guns will almost certainly need to be torn apart and rebuilt straight from the factory. The plants in which they are assembled are obviously concerned more with quantity than anything else...but I cannot fault them. They are used as training aids, with their intended purpose being primarily decorative. A prop for exercise. How much mechanical function do you need for that? These complaints are from a man who wants to use it as a gun instead of what it was meant for.
Lots of burs and sharp edges. They must be cleaned and filed. The grease is also thick and abundant and has the lubricity of gravel and honey. The gun may have only cost you $10 but you'll spend four hours properly cleaning and deburring it. How much is your time worth?
All in all, after getting some work done it's a pretty fun little gun...it's just a matter of how much work you want to do.