compared to the 2ce Sig and 3a Sig, the mids of the 1c are recessed at the woofer-tweeter crossover point. it depends on you if you like this characteristic. some like it because it makes the speaker sound laid-back; but some see this as lack of detail.
however, the 1, 2, and 3 all share the typical vandersteen characteristics of a big and open soundstage, and well damped bass (linear and extended, but not punchy). it will sound outstanding and natural when reproducing acoustic double-bass, but pop fans will be disappointed when reproducing the synthesized bass of modern music.
in terms of setup, speaker placement is critical due to its wide-dispersion design and use of 1st-order crossovers. setup mistake will result in peaks and dips at the crossover point/s. just ask AudioAmp to show you how detailed its setup manual is.
trust me on these. i am speaking out of experience of owning the 2ce Sig.
hope this helps