+1.
Going back to my original post, you will notice you can buy those track ends with a derailleur hanger from surly, easily. The average first client type dude is almost certain to be pouring over a Surly catalog.
There isn't anything wrong with the drops in your original post. And they have a cool factor that might help close a sale. The reasons not to use them include:
1) expense, which can be a positive
2) complexity, you have to keep and not loose two sets of ends, and your drops are attached by screws, which is also ok, but now maybe we are talking locktite. All this assumes the dude who did it got all the tolerances right, particularly the screw ones. and he may have.
3) time. It will take longer to switch those over. And you will have your chain caught in the rear end, and need to break it or use link. Though these are not the only ends with these issues.
4) Difficulty of install. If you are a newbie to all this you will have the following challenges:
a) what looks a like a stainless to non stainless joint, minor complication or cost factor
b) If you blow the heat thing you may distort these babies so that they don't work that well with all the precision parts.
c) worry factor over wrecking expensive parts
d) Breezer type hood which isn't a go with all four main systems, and their skill sets.
Of course this is all good or bad depending on what you are after.