I always wanted one of these. Back when they first came out, they were well worth the asking price of around $600. ( 1970 dollars.) Today they provide all the advantages of the TenTec Omni-D without digital readout, variable selectivity, QSK, and frequency stability.
The 210x is an all solid state 100 watt transceiver with single conversion receiver, 2.2khz selectivity, audio derived AGC and serious drift problems. The 210x covers the 10 meter band but does not go all the way down to 28.000mhz. It does not cover the WARC bands and is a very poor CW rig. It is pretty good on SSB. It comes with a console that adds VOX and provides a marginal power supply.
The passive mixer makes for a very quiet receiver and once the pilot lights are changed out to LEDs, receiver current is on the order of 300ma making this radio a good choice for battery operation.