I received a 7mm Burgess/TMB Planetary eyepiece today.

What I really would have liked is a 6mm but they are still not ready, and through circumstances which I will not go into here, I had the opportunity to acquire a 7mm, so I did for the purposes of evaluation. I have been comparing it with the 7mm Pentax XW tonight in the 8" f/6 Dob. The XW costs over 3 times as much as the Burgess so this is hardly a fair contest, but don't let that stop me.
This is not a thorough review, just what I gathered from a few hours of viewing in average seeing under light polluted skies.
What you get for around $US99 ($US110 with postage from Burgess) is amazing.
Photos show (from left to right): 7mm XW, 7mm Burgess/TMB, 8.5mm XF, 19mm Panoptic, 9mm HD ortho.
Coatings look excellent, something between Televue and Pentax coatings, but more like Televue.
Both eyepieces were as sharp as seeing allowed. I noticed nothing between the XW and Burgess ito on-axis sharpness.
The Burgess/TMB showed excellent colour correction. Less lateral colour at the edge of field than in the Pentax (at the edge of its larger field). If you put the Burgess' smaller field stop on the XW (to make its FOV the same) then the colour correction would be comparable. There is just a hint of colour around Jupiter at the edge of the FOV. The Burgess is better in this regard than what I remember of the 5mm Radian in the same scope.
Neutral colour rendition. Similar to XW.
Sharp to the edge. Not a hint of field curvature or astigmatism. This is in an f/6 scope but I have no doubt she'll go faster.

The XW shows a bit of blue flairing from bright stars (e.g. alpha centauri) at the very edge of the field. The Burgess has virtually none of that. Again, the Burgess gives a similar view to stopping down the field of the XW.
Plenty of eye relief but considerably less than the XW. The EP is very comfortable regardless. Adjustable eyeguard extends a lot more than it needs to for me. I suppose that would come in handy when barlowing the EP which would extend the eye relief.
The EP is very well baffled. There are no reflections or glare when bright objects are in or near the FOV. I tried moving Jupiter here there, just outside the FOV, on the edge, etc, then repeated the same exercise with the Moon. I could not get any light flares, reflections or obtrusive stray light happening despite my best efforts.
The XW shows slightly less scattered light on bright objects, Jupiter and the Moon in particular, but the Burgess is very good in this regard. Certainly better than the Stratus or Nagler T6 (but the T6 is a strange design with a highly uneven distribution of scattered light across the FOV).
Perhaps related to the above, the contrast and/or transmission of the XW seemed a smidgen better on open and globular star clusters. But I could not satisfy myself that this was indeed the case, or if it was just the impression I got from the larger, more immersive FOV of the XW. I could not find any stars visible in one EP and not the other. Neverhteless, I fairly consistently got the impression that it is just a little bit easier to see things in the Pentax.
The magnification of the Burgess also seemed perhaps a little higher than the XW, maybe up to about 5% higher. I could not ascertain this though. The difference in magnification could also be responsible to the perceived better contrast/transmission of the XW. 7mm is fairly high power for an f/6 scope and DSOs start getting too dim at higher powers.
Edit: Now that I think about it, there is no differences in views through the two EPs that cannot be explained by the smaller-than 60 degree FOV of the Burgess (see below).
FOV is specified as 60 degrees. On comparison with the 60 degree 8.5mm Pentax XF, the Burgess' FOV is slightly less, probably 56-58 degrees. It feels noticeably less immersive than the XF or the Meade 5000 Plossl (also has 60 degree FOV).
The adjustable eyeguard works well, but the mechanics feels a little rough compared with the XW and there is grease/oil on the threads, like the Meade 5000s have. I had to wipe the barrel clean when I first extended the eyeguard. After that the grease did not return with repeated adjustments of the eyeguard (unlike the my 5000 plossl).
I think that's about it. I have seen enough of this EP to know I will be ordering its 6mm brother when it's finally ready. The XW still rocks my observing world so I'll be putting the Burgess up for sale soon.