re: Bandsaws

I don't have any advice on where to buy.  But regrading BB guides with metal, every bandsaw I've used that was dedicated to metal had BB guides.  That's vertical, horizontal and portable ones.  I've never used cool blocks with metal so I can't say how it would compare but I would probably stick to ball bearings without a good reason to try blocks.  One possible issue I can see is swarf building up between the blade and the blocks causing the blade to run hotter.