There's a number of things that in my opinion are improvements over over the Yoder. Firstly its box like multi rack design allows for much more usable cooking area over the traditional round smokers and the fact that is got 2" insulation should provide more consistent cook times all year around. I also like the fact the fire is in a separate chamber so I should be able to rig up my Smokai cold smoke generator more easily than with the Yoder and the cabinet style chamber means i'll, be able to hang meats & sausage which is a big bonus as ive been doing a lot of smoked charcuterie and sausage lately and frankly doing it in the YS1500 can be a pain in the arse.
As for the price it's all relative but there big deals to be had with this brand currently with around 40% off RRP and I bought mine from the place I work which also helps immensely as I wouldn't be able to afford it otherwise.
Looks like the company making them are these guys in Hungary https://www.bbq-pitbox.com/ who seem to be adding a few cosmetic changes specifically for ProQ.