I wouldn't call it crap, but a great big white Canon wonder tele it is not. You get what you pay for.
Shooting really long lenses, no matter how good the lens, will really show any flaws in your technique. Tripods that you swore were rock solid turn out not to be; you get a whole new respect for wind; heat waves become an issue. In short, any flaw in the system becomes magnified in ways you would never imagine.
Now, with a slow, dubious quality lens, you throw in other factors. Focusing at f8 can be a real challenge in all but bright light, and some camera screens just don't do well with long lenses to boot. The lens coatings are not the best in the world, so you need a really good shade, which you will probably have to make yourself. The tripod mount on the lens is rather shaky, so you will need to deal with that. The lens is so slow that it fools the meter in my old pentax, as more light gets in the viewfinder around my eye than comes through the lens.
Once you learn to deal with those sorts of things you can get decent photos from it. Within its limits it will perform, but you really have to do your part.