I have it on the dash so I can easily see which frequency is being used when I hear activity, I had my old 2054 mounted under the seat and through the stereo, but it was always a pain trying to guess who it was that was transmitting. It can be cleaned up some, especially on the dash, I have just gotten so accustomed to it that it doesn't really bother me, and I haven't had any run in with the law so it doesn't seem to be an issue.
I thought about mounting the mini phantom above the mirror, although I prefer using the mirror mount as opposed to the window mount, as it seems more secure. I plan on adding one to the rear window as well.
The trunk lip mount is probably the most professional looking thing I have, haha. I bought them for $25 shipped each on ebay and they have been great so far. Once the winter is over I may get arround to re-arranging my equipment for a better looking install, although as I said before I don't want to permanently mount them anywhere.