GeneralR's "Enhanced editor" is a tool dedicated mainly to scenario designers, that offers them further options as far as units are concerned, and also eliminates some of the editor's constraints.
This is not a unique utility, other similar ones include Julius' "Designer's editor". However, each of them have their own utility at this point, none of them being perfect.
The main usefulness of this particular utility is the ability to juxtapose buildings without having to resort to map copying, which saves time and allows for effects that cannot be easily created otherwise. This is indeed very useful. However, as Basse commented previously, there is still no option of piling gaia objects on top of each other or on top of buildings, which would have made this so much more useful.
I can see the utility of this .dat file being used alternatively with Julius' utility, as each of them allows for things that the other cannot (Julius' allows for gaia objects piling, and has a more organised list of new objects, while this one allows for building piling and has some useful objects that the other doesn't , such as the Cobra). I have tried using both utilities on the same scenario and the result seemed to be stable. However, it is tedious to copy and paste data files all the time from one place to another, so I hope in the future there will be one utility that covers all of these aspects.
Though the utility of this file, as I showed, cannot be put into question, its quality and instructions need a lot more attention. For one, there are no instructions, and one who is not familiar with data files and data editing will be feeling lost upon downloading. The .dat file doesn't even have the proper name, and it must be renamed as empires2_x1_p1.dat. This instruction is not provided, which is why I recommend the inclusion of a readme file that clears up these things for beginners.
Another problem is the fact that there are no instructions regarding the new units included, many of which I feel have little if any utility, and only crowd up the editor's lists. I recommend the author to take a look at Julius' utility, who has taken the time to include a list of the new objects and units, as well as their possible uses.
The .dat file itself is stable, and I haven't experienced any crashes or bugs.
Despite it's drawbacks, there are lots of things for which this utility can be useful, such as city design, or easy integration of beta units in a scenario. This is a good download for people who know what they want to achieve and are aware of how this file can help them (probably only partially) towards that goal.