All previous testing that I've seen with battery powered units has been pretty similar. They start with projectors which are rated at one power level - say 300 lumens. In reality, they find that the projector only delivers about 150 lumens. Then, in battery mode, it drops down to about 75 lumens.
In a 'business' presentation, under normal fluorescent lighting, you need about 50 lumens per square FOOT of screen space. So, you get about a 20" diagonal from these portable models from a typical setup.
They aren't bright enough for solid business presentations. Especially considering that there are brand new inexpensive business models which push out a couple thousand lumens for around the same price.
Now, the battery option and the 800 lumen rating go nicely together, if you can actually get the claimed 90 minutes from the battery while at full brightness, and it comes close to the claimed specifications.
But, I would not bet on one of those things being the case.
Still, AAXA is one of the better companies out there with a longer history than some of the others and their focus has been on the LED/Pico/Micro market for quite a while. It certainly is the most likely one to come closest to delivering on their promise. It would just be nice if they got their products into the hands of serious review sites a lot sooner so their product could be put to the test in a more unbiased situation.