What's the comparison between a plate heat exchanger and a shell-tube heat exchanger?

Question

in terms of ease of assembly, heat transfer effiency, heat losses, etc....

Answer 1

Shell and tube heat exchanger:
http://en.wikipedia.org/wiki/Shell_and_tube_heat_exchanger

Plate heat exchanger:
http://en.wikipedia.org/wiki/Plate_heat_exchanger

Answer 2

Any comparison would have to be made on the basis of what materials you are heating or cooling and what temperatures you need to maintain.
There are some conditions where a shell and tube exchanger is the best to use for the application, and some where a plate and frame exchanger is best.
For instance, for materials that have high fouling factors, or are very viscous, a shell and tube exchanger would be best because a plate and frame unit might plug up, and in another instance for very corrosive materials many times a plate and frame unit would be much more economical than having to buy a high alloy shell and tube unit.