Mathmos has great globes.... however there's is always a chance of getting a bad one. All of the Mathmos lamps I own have very few, and some have none at all. My Giant dose not have many bubbles they where hand blown globes.
Glass flaws drive me bonkers...hard to see past them. o.O
Out of all my USA lamps id say 80% of them have GREAT glass, with very few bubbles but not completely free of bubbles. The other 20% do have bubbles, some quite a bit, but i cannot tell why some have bubbles and another USA globe from the same year dont.
90% of my China globes are pretty bad with one or two being really bad. I have now 3 grandes, they all have way better glass quality than i expected but still a couple bubbles and some scratches.