I have not used chillers before but know a bit about them in my industry. Thermo chillers maintain a stable temp gradient when it has reached its steady state but takes a longer time to reach the desired temperature. As for normal chillers that use refrigerant, it can reach the desired temp faster but its temp gradient is more erractic, meaning it goes up and down as the thermostat switches on and off as it hit the set temp. IMO, in terms of cooling abilities, normal chillers are more powerful and good when MHs are used. For TE chillers, it is less powerful but can maintain a more steady temp, the it is depentent on the surroundings of the body that requires cooling. Correct me if I'm wrong and it is only my 2 cents worth!