If you can get the ML's for $1K, I would do it. I remember them going for $2500-3500. They have a very clear and transparent character.
Are you using a sub (or subs) with your system? If not, it could make a world of difference.
I have two M-500T's in my system- one is MKII, the other is not, as well as a Sunfire Signature sub. Not only can I "feel" the music, but my neighbors can as well. I do not play it extremely loud, but I do enjoy music that occupies the whole spectrum.
One pair of speakers I have is very efficient-vintage Klipsch Cornwalls, the other set is not efficient-Tesla Sonorous. The 500T's both do a great job with them.