Just wondering..
What countries is it most played in?
It's extremely popular in Malaysia and Thailand. I know in Thailand there are foosball halls (like pool halls) with multiple dozens of tables. Malaysia is home of the "Torpedo" foosball table, which is an exact copy of a Tornado (I understand that it's illegal to sell in the US since it violates a bunch of patents). I know a Tornado pro who played on one and didn't even notice it wasn't a Tornado for the first couple of hours.
When I was in South America they had tables that sloped down toward midfield; stopping the ball was illegal (basically it was always 1-ball rollerball). They also had the crazy Futbolin tables with circular feet on the men. I'd say overall it's less popular there than here, though judging from the turnout at World's the past couple of years Costa Rica has a lot of players--I know they have a Tornado distributor there as of about a year or 18 months ago.
Foos is also played a lot in Morocco (we have a bunch of Moroccan players locally). No idea what tables they use.
Other places that play: France (Bonzini tables, grippier and slower than Tornado), Belgium (Jupiter tables, grippier than Bonzini), Austria (Garlando/FABI), Italy (Garlando/Fabi), United Kingdom (Garlando/Tornado), Germany (Garlando/Lemacher), and Hungary. Canada uses Bonzini in Quebec and elsewhere it's Tornado and Garlando.