There seem to be very little "cross experience" with both roasters (or comparison of the Allio with any gas roaster). When the Allio prototype was announced (about two years ago) there was some interest in this forum, but I haven't seem much here lately.
There are forums for Allio users, as well as a FB group. From what I read there, most users seems happy with their roasters, even though the constructors are still fixing some construction flaws. My personal opinion on the Allio is that it's an advanced hobbyist roaster, which indeed produces good coffee. It got all the modern bells and whistles, like dedicated software, USB connectivity etc.
The TJ-067 on the other hand builds on a traditional type of professional roasters. The 1kg capacity is under-stated, i.e the whole system is built for maybe up to 1.5kg. If you want you can roast with it all day long, producing up to maybe 30kg of roasted coffee without a stop. (The limit is the stamina of the operator, not the roaster.) There is also no doubt that the TJ is capable to produce professional grade coffee with precision and repeatability. The TJ roaster is often discussed here as well as on a dedicated forum for TJ roasters. From what I understand, the product support from MillCityRoasters is nothing but excellent.
I personally have a few years experience with a Huky500, which with some care can produce really good coffee. The TJ-067 was on my shortlist when I purchased the Huky, but as I didn't have any garage (or similar) hauling a 250# roaster up to the third floor wasn't an option. There are a few guys who have upgraded from a Huky to a TJ-067 and they all seem very happy.
To conclude my thoughts, I find the Allio Bullet alluring, but I'm not sure about if the people reviewing it can compare the roaster to e.g the TJ or any other type of pro-grade roaster. I don't know your ambitions with your upgrade, but you will not go wrong with the TJ-067. (... and a bottle of propane will get you a long way.)