I have eaten vegetarian sausages, hot dogs, and other faux meat dishes. Some have been excellent and others have been foul and awful, as you mentioned. There was a vegetarian restaurant in Buenos Aires that was particularly good. Argentines are the world's most serious beef eaters and would be harder to convince than most Whole Foods addicts.
I would say that the taste and texture of veggie dishes depends on the process by which they are made and cooked.