—It is generally accepted that Stanley’s pre-war tools were of higher quality than pretty much anything they made after 1948 or so.
—To discuss preferences amoungst the planes made (and most commonly available to this day) between 1900 and 1948, galoots talk in terms of Types. Those Types identify the styles of knobs used, dates on the bed of the plane, logo (or lack thereof) on the lever caps, frog style, etc. Much of this is personal preference only.
—Bedrock vs Bailey is marketing. There. I said it. But others will disagree, some very strongly. The essential trait of bedrocks is the larger mating surface of frog to bed of plane. You’ll have to pay a premium most times to get a bedrock, and you likely won’t notice the difference. Leave those for collectors and/or the severely afflicted. :-)
—Within Stanley block planes is where you’ll find the biggest potential for clunkers, as the company mades scores of blocks and several aren’t good for much at all if you’re looking for a serious (and versatile) user block. Go to Patrick Leach’s Blood and Gore site to see and read more about stanley planes than you ever imagined. I’ve spend countless hours there, and learned alot.
All my comments are Stanley specific, as that’s what I know the most about. Not an expert, but an enthusiastic user of Stanley’s original Sweetheart era tooling. :-)
Good luck, and others will certainly add to the discussion!
-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive