Very good amp, but quite old, if it is in good condition, the age doesn't matter much, the price is perhaps a bit high, but they don't get sold all that often as they sound way better than what you'd get for close to the price. Your speakers have to add the tonality you want with these, they are on the sterile side of neutral, but I usually enjoy that in an amp and let the speaker colour to the sound for you.
BTW it does not deliver 100w into 4 channels, but into 2 - it just has an A/B speaker facility