They are one of the greats (though, based on second hand info, I think they were surpassed by the Model B). Audition them! I don't know the market now but they weren't cheap new. Do a search on Audiogon to get a sense of the market. But I'd say if you have the money get them.
Snell was run by Kevin Voecks, who now is the head designer of the high-end Revel Salon speakers. Snell made a number of excellent speakers. He was, and is, by all accounts a thorough, scientific and gifted speaker designer who values accuracy.