Purchased a pair new in 78, my brother now has them. Good luck finding a pair, rare as hens teeth they are, didn't know that when I gave them away lol.Listen to some AR12's if you can find a set. AR9's are an impressive wall of sound but the 12's have scary good midrange detail.
Haven't had the pleasure of listening to LST's.
Of my various AR's, 90s, 92s, 18s, 58S, and AR-1MS mini-monitors, I find my AR58S speakers the most addictive. There's warmth and detail, bass extension and midbass definition, plus clean and clear midrange and high end. Not overly bright, at least in my system, but there's a midrange presence deserving of decent gear. While I've never heard a bad set of AR speakers, my 58S' are a lot of fun, and aren't going anywhere.