The matter of whether or not acting technique is better today than it was in the Elizabethan era is really a matter of artistic preference. One could argue that today, actors have the opportunity to take more time to "get into" character, and potentially work in character detail from a number of previous interpretations.
As for the conditions actors worked in, things are certainly much improved! In the Elizabethan era, theatres were typically cramped courtyards, though having freestanding theatres (such as the Globe) did become more common. Courtyard and freestanding theatres were often unhygienic as people left food scraps and personal waste on the ground. Gathering lots of people together in close quarters was also an exceptional means of spreading disease, like the plague.
Theatres built of wood frequently caught fire, which posed a big risk to the actors and patrons. Costuming had its dangers, as makeup contained hazardous materials like lead (as for white face paint) and mercury.
Actors were historically one of the lowest classes, along with sex workers and other people who "danced for their dinner." Being low-class in any society and time comes with its own stresses of health, safety, and survival. Women were not allowed to act, though today there is much more gender equality in acting and it is a desirable profession for many people of all genders.