I have been messing around with my new bandsaw (Rikon 10-345) and fine tuning the guides and the heavy vibration that I had initially is gone. Just a gentle hum now. My thrust bearings were set to far forward and they were trying to push the blade forward as it ran and caused it to vibrate like a mo fo.
This is an awesome machine. I was a little discouraged when I read people knocking this saw, but I think it does great job.
The top wheel does have a little flex in it when you grab it at 3 and 9 o'clock, but I don't see it effecting the blade at all. I first heard about this grab at 3 and 9 o'clock from the Laguna video I ordered when I was considering there saw. Mr. Laguna states in the DVD that you should not buy a band saw if the upper wheel wiggles when grabbed at 3 and 9 o'clock. I am convinced now that this is nothing short of a marketing gimmick.
I bought and installed a 1/4" Timberwolf blade from Woodcraft tonight and so far it performs excellent.