Clan has summed it up well, the CVT can be an acquired taste and doesn't operate like a conventional torque converter style gearbox, but I certainly enjoyed the one I drove briefly.
Ideal for a hobbyist, there are a select few people that understand the system, but personally I'd buy the car and drive it - it'll be fairly obvious if something is wrong, ie. very high rpm at low speeds. If you get stuck post here or on the Volvo 300 Mania forum/facebook group. Don't rev it in park too
