I recommend the D-Links as I have a lot of them form outdoor to indoor and they have been rock solid, no problems and they just work with no other needs. Set them up one, which is easy and away you go.
Cisco is good and high dollar stuff. BUT, I am not certain why (other than an Agreement for better pricing and salesman commissions and I am only speculating), that they would recommend Cisco because of metal buildings and obstacles.
RF, Radio Frequencies, no matter whose device sends them out, will react the same when confronting a reflective surface.
Now, I have not compared actually frequency tolerances, RF receive sensitivity, actual power output and the signal quality in db at a meter, but you might get yourself a good spec sheet on the RF characteristics. More sensitivity and a better power output beyond the antenna, usually represented in db, can show better engineering in the RF stage. Maybe the Cisco has better error correction which will mean less time, less latency of the data packets.
If you need better range/sensitivity, for either AP, you can add a direction high gain or omnidirectional antenna.
That's my .02 cents anyway. I believe both are good. I also know that the Cisco may be a bit more difficult to set up but it has a lot more software features that it sounds like in your environment you will not need.
John