1) Filter type: HP,LP,BP,notch, All Pass, custom
2) characteristic: Burterworth, Bessel, Linear Phase, Chebychev, Raised Cosine etc
3) Pass Band gain (dB)
4) BW -3dB point
5) Bandstop attenuation (dB) @ f OR filter order
6) Output current, Slew rate, output swing
7) Output Offset error, Gain error , tolerance stackup (Input offset= Iin*R mismatch, Vio, Iio)
8) Output Noise level from gain and input R and input V,I per root (Hz) BW
9) Cost, Package ( Quad, single ) SMT or THT
etc