The title says it all. If you want to tame an amp with too much high mids, this is the speaker for you, as it delivers the traditional Celestion voiced-clarity with a good emphasis on the low-mid territory. The treble is still there, and the lows are very good too. I sold my Vintage 30s, which sounded a little too agressive with my ENGL Blackmore, and I definitly prefer these. Mind you, I like V30s with lots of other amps who benefit from a more open-sounding speaker, but with my ENGL these sound much more balanced and thicker, both miced and in the room.
The sensitivity rating at 100dB does seem a bit misleading, as the tamed high mids make this speaker sound a bit quieter than the louder V30s I had before. But I don't see that becoming a problem, unless you're planing to mix speakers in the same cab - in that case, I'd rather mix it with something like a T75 or something with similar output.