I have. They do nothing to distract from the ambiance - if anything they add an extra layer of magic. The added lighting gives it a total 'wow!' effect - at night, it's not just the screen that lights up - there are extra spotlights that illuminate the player(s). It's magical both for those playing and for those passing by.
As for the portals you mentioned above - you do know that when the stone portal isn't on it looks just like stone right? We literally had to search and search for these portals. Even with the lock boxes, they are so well hidden it can take forever to find them.
ETA (this portion below not directed directly toward Amused to Death
As for it distracting in Liberty Square during the MSEP, you have got to be kidding. First - the whole portal by the Liberty Belle is covered by a curtain that opens only when key is used. IF it works during the parade (some portals supposedly are disabled in Fantasyland during Wishes as the CM's prepare for the fireworks fallout zone) and IF you can even notice it over the music playing from EVERY SPEAKER along the path of the parade and the noise of the 400000000000 people packed along the parade route (7 people deep with another 8th layer of people standing in the area the poor CM's are trying to keep clear so that people can move to/ from SM and BTMRR) then something has gone terribly, terribly wrong. IF you are standing by the Liberty Belle portal trying to watch MSEP, you aren't seeing much but the tip top of the floats anyway. And IF someone wants and unobstructed, uninterrupted view of the parade with ZERO lights distracting them, they should arrive early with a team of bodyguards to confiscate the 4 billion cameras and video cameras with flashes and outside lighting that go off every. single. second. of the parade.