The New Advents are a classic and still sound great. Make sure the foam surrounds of the woofers are intact, as they tend to rot after 10-15 years. I owned mine for 25 years, replaced the woofers once, and sold them here on Audiogon to a guy who continues to enjoy them. Smooth, good bass extension, and pretty eficient - I originally ran them with the Advent 300 receiver, which only made 15 W/ch. The beautiful real walnut veneer was just icing on the cake.
If you find a pair of older Large Advents that have had the original tweeters replaced with the orange fried-egg tweeters, they would be sonically equivalent to the New Advents. Again, check the woofer surrounds carefully for rot. There are plenty of places that will replace the surrounds for you, but you need to figure that into the price. Good luck!
David