I know little about the Maggies and nothing about how Blue Circle might work with SF's, but can say that the Signum is a special speaker with unusually good sound at its price point. It was designed for maximum transient response, and uses an unconventional surround/suspension on the mid-woofer that makes the driver really fast. Assuming you do not require deep bass or have a large room, it is welcome in top systems. Aside from the Guarneri, it is the best small SF monitor, and is unfortunately now out of production. It requires quality amplification (but not a lot of power).
If you want a more full-range speaker that can do orchestral music and rock, the Extrema is the best in the line (and some would argue, the best SF ever made other than the Stradavari), but it is also unfortunately out of production and requires a beefy amp. The Electa Amator is a nice speaker, but less distinguished.
If you want a more full-range speaker that can do orchestral music and rock, the Extrema is the best in the line (and some would argue, the best SF ever made other than the Stradavari), but it is also unfortunately out of production and requires a beefy amp. The Electa Amator is a nice speaker, but less distinguished.