The price might make me a bit suspicious - but if it's working, that's a good deal.
EHam has reviews on this radio (for the most part, pretty nice ones), Kiwa does both selectivity and audio mods, and - surprise, surprise - there's even a fairly active Yahoo group for this radio. Given how old it is, that's quite a shock.
There are 2 known weak points with radios of this era - the selectivity is a tad on the wide side, and it is known to overload if you put too much of an antenna on it. If memory serves, there's a switchable RF Attenuator, but it gives you steps of I think 10db. You might want to build one yourself, and put it inline with your antenna (easily done if you have a good junkbox).
But definitely a keeper. Put a decent antenna on it and you're good to go.
The Kenwood R-1000 is a a high-end HF receiver. It's an older model, late 70's early 80's but it'll certainly get the job done. With a decent antenna you should be able to hear just about anything on the HF bands including military.
The radio used in good condition usually goes for around 300-400 dollars, here is a picture and info of one.