I am a regular EE4 user. The primary benefit of using EE4 is that when
you enter your building's parameters, it automatically creates a
reference building that meets the Canadian Model National Energy Code
for Buildings (MNECB). It is a graphical interface which runs the
DOE-2.1e calculation engine. It comes bundled with CWEC weather for 43
Canadian sites. By default, it deletes the supporting DOE files, but
clearing a check box will give you the raw DOE input and output files
for both the reference and proposed buildings (proposed being the
entered building, reference being the MNECB building). Data entry is in
either of SI or IP units. One of the best features is the wall U-value
calculator. It explicitly demonstrates the impact of either wood or
steel framing passing through insulation layers. There is a useful
modeling guide online.

On the downside, EE4 has a tree-structured data entry with no CAD
interface. (In fact, there is no X-Y coordinates to any of the exterior
surfaces.) Thus, building envelope take off data entry is much slower
than in a tool such as eQUEST or VisualDOE where the CAD drawing can be
imported and traced. There are less mechanical systems in EE4 then the
DOE-2.1e engine and there are some workarounds embedded in the
software. (e.g. heat recovery on zonal type systems is achieved by
reducing the supply fan volume in the proposed building.) There is no
provision for running parametric runs within EE4. If your project is
not in Canada, you may have to define the building and then run DOE as a
standalone to use weather data not included in the Canadian data set.

On the whole, I prefer eQUEST and will use it first -- primarily for the
greater speed in defining the building and doing the envelope take
offs. Unless you are creating models and comparing them to the Canadian
MNECB (which I do fairly frequently), there is no significant advantage
to EE4.

Hope this helps.

Brian Fountain