I believe the raw glass material, most likely american boro, is superior in strength to china glass, even china boro. I also like MLglass's quality but I did have an airhole in a recycler. And I do like CCG's quality and their percs but TAG pieces just seem a bit more sturdy/durable. As for steven's pieces being similar designs...they're all mothership knockoffs so they're gona look alike.
I'm not saying I'd rush to pay more for a similar piece but I do still believe they are better quality in glass durability. But the differences are small enough that it is hard to tell unless comparing them in person. Are they worth the price? I would rather buy 2 or 3 CCG pieces with the FOL/SOL perc so I guess that answers that.
So to stay on topic I would recommend CCG, Steven, or Mlglass to someone who is looking for a cheap glass bubbler since TAG's glass is more expensive, but less hassle and better glass.
p.s. Thickassglass was originally called Thickqualityglass