If they are in good condition they are worth it, and no, the ribbon maggies only outdo them in dynamics and in the ribbon tweeters' better top octave. The later ones (Spectra models) perform better on dispersion.
The servo amps are great and make a great value speaker into a great speaker. But you need a subwoofer when you use the servo amps (limited power). A sub is also good to have for ordinarily amplified Acoustats - they do reach deep (3 and 4 panels and up to 6) but with limited output/max volume, the bigger the speaker the louder the bass max loudness.
The 2+2 and the spectra equivalent are 4 panels per side. Once the transformer/interface circuits are updated or servo amps restored the speakers are still competitive with most new electrostats.