I made a similar purchase a year ago - but paid a bit more - $275. Best money I ever spent on speakers. They have the traditional 'polite' Celestion sound, great imaging, tight bass (such as it is), etc. I'm curious how SL6's would sound in the same room, or in other words, whether the extra driver helps or hurts. I may buy a set just for fun to see.
Only downside is you need a powerful amp - those Celestions are very inefficient. And forget getting replacment parts - particularly the tweeters, which can go bad on you.
Enjoy!!
Joe