These are pure vinyl/rubber planks. There is no warping and very very minimal changes in size. These issues are unfounded.
Now personal opinion: I have personally used these (not the exact ones but the brand) planks and I have used other pure rubber planks and I have to tell you that I have been very happy with them all. The only thing I will say is that on the pure rubber side the planks are usually expensive and sometimes the top doesn't look non-rubberish.
As for the click lock mechanism, this is always something you should test at store. I have personally never had issues with the Allure brand. As for their mechanism I would give it a solid 7 out of 10. You do have to get under the installed row which does cause an issue that you can unlock something while locking something in but it is just a simple puzzle to solve and when in place it is good to go.
As for criticism, first you could lay this stuff in a pool and it won't warp or bend - it is pure rubber. So not sure what product they were rating or commenting on but this is not right. Second if people have gaps it is because they have not locked something together correctly on a previous row. These issues compound until you can see a noticeable gap. This has nothing to do with the locking mechanism working or not, the user simply didn't install right.
As for warping or size changes due to temp or humidity, like I mentioned before this is a non issue. Are planks better than squares? It totally depends on the subfloor. I would only glue down vinyl if it were in then sheets on a very flat floor or if it were in a commercial type building (apartment building). Most home floors basement or main floor do not have concrete that is flat enough to support glue down directly on concrete.
And as far as install on this brand I can do a very large bathroom 8 by 15 and go around vanity, toilet, shower, whatever in about an hour - I have installed this brand and similar 25+ times. It cuts with a knife like drywall (or you can use a mitre saw) and snap clean. Out of all of the flooring choices this is the fastest to install, the most durable, and least amount of prep. The downsides are it is a bit cold and just might not have the look that most people want.