If you do a search, there was a pretty good thread on bandsaws sometime during this past year or so. Dick Neighbors gave a lot of good info. At the time, I believe the consensus was that a 14" is about the minimum size for veneers, recuts, etc. And yes, correct setup, good quality blades, and good technique are all necessary and you can good results. The better quality bandsaw you start with the better too. Rikon, Laguna, and Grizzly are notable names. The Deltas - especially the newer ones with built in tension release - can be a good saw too.
The 12" saws mostly tend to be 3 wheel saws and getting the blade to track correctly can be difficult.
That said, I have a 14" Central Machinery (Taiwan knockoff of the Delta) that I have upgraded the table, blade guides, and blade (TimberWolf) and tuned up a lot. I also keep a small Delta 9-10" saw handy with a metal cutting blade mounted on it. Any metal work I do is pretty much with small sized pieces.
CraigsList can be a good source of bandsaws - most homeowners use them lightly, so a good one in near new condition can often be found for half (or less) the cost of a new one - you may have to wait and watch for a while, but they do show up.
My 2 cents,
Gary