I was about to order the Visual Garage Shark Fin antenna, but then came across the Beat Sonic one. The BS is $45 MORE than the VG one. Personally, I like the looks of the VG over the BS. MY only issue is I can't seem to find anywhere that shows the dimensions of the VG. A friend of mine has the VG on his GR STi and loves it. It works and looks great. Both come painted in your cars OEM color.
The next part I'm also torn on. Color. I ordered a satin white pearl BRZ, however, I'm planning on doing a gloss black vinyl for the roof. So do I order a white antenna or black. I did this on my old TL Type S and tried to vinyl the antenna on it and it didn't work out too well, so I bought a black roof antenna and that completed the look.
http://visualgarage.com/home.html
http://www.beatsonicusa.com/fda43.html