Would anybody give their impressions about the differences in sound between the MG944 and HDT?

I've got them both set up. I'll report back in a day or two.

Sorry this will take longer but yes this will be interesting Will.
I am finding that after a long sit the HDT are breaking in more. Another caveat is that I do not have the Decware driver in these. This pair of HDT is a bare MDF (no exterior finish) that I had fitted with port tube fittings at the bottom so the tube lengths could be played with and all three pipes are at stock lengths within a half inch. These HDT don't have the Decware modified Fostex driver but rather the Tang Band W8-1772 8" Neodymium Full Range Driver. They are similar in sound to the Fostex but as for T&S params not certain how they compare especially with regard to the foam surround Decware adds to the Fostex unit.

Right off the bat the HDT with the Tang Band is really really good in the midrange. Not to say the MG is not good just more laid back than the HDT. System synergy is key here. Both speakers are revealing. The HDT as I recall with the Fostex is "ruthlessly" revealing. Decware adds a foam surround that helps with cone edge distortion artifacts which the Tang Band driver does not seem to have since the outer edge cut of the main cone is exposed on the Fostex and the Tang Band inverted doped cloth surround is applied wrapped around the front edge of their cone material for a softer rolled edge. That being said a $500 set of TB should by all means sound pretty darn good.

The octave into the mid to lower 30 Hz range is represented very well with the MG944. The HDT not so much yet the HDT has a punchyness in the 40s that is just a bit more dynamic in that particular range. Both even out the score in the mid bass range from 60-150 Hz.
To say they are different sounding is an understatement yet they both sound very articulate. The MG has a more tipped up low bass response per a given input. They are darned close to each other sensitivity wise.

The MG is laid back in the mids and has more apparent weight. At one time I lauded the MG for being what I call a very transparent "box less" sounding speaker. I still feel that is an apt description. The HDT in the state I have it with the TB driver takes the transparency to more better. To say the HDT is weak in the bass is not true. To say the HDT wants more weight and bass drive in the upstream components is true. Unfortunately the experimenting with different drivers is not going to happen for me any time soon. Too many things to take care of here outside of hi-fi.  :(
I'll post more later with my impressions of lower power tube amps and some SS amps I have running everything through a Decware CSP2 pre

Yes, thanks Chris. Looking forward to more impressions as you refine the HDTs.

I get the boxless thought on the MGs. I remember telling Bob that I thought the speaker vibration themselves sounded like the cello wood as I listened to Solo Bach....I think this may have unnerved him a bit with all the attention to damping, but I was trying to describe just how much of the cello wood I could hear, and it did not sound like it was coming from the speakers. The MGs never look like they are a part of the sound to me.

Mine were made at the time with early plinth setup, and before the crossover coil. I did put in the coil and new caps, but finally went back as I thought it created a subtle speed reduction with the coil in place (especially noticed on drum attack, depth and decay), but also they seemed to introduce a subtle "correctness" in the balance that I found a little unnerving. I guess I like a little tension in the presentation. Subtle stuff in fact, and all preference, but you know...that last percent or so means a lot at times.

It is really interesting how powerful little stuff can be.