Dan,
I have a Lee Classic Turret press and I like it very much. Just to make sure we are talking about the same press, here is a link to a picture from Lee's website.
http://www.leeprecision.com/graphics/shoppingcart/ClassicTP.JPGYes, there is an auto advance mechanism that rotates the turret head one quarter turn at every cycle of the handle. It works well. I have removed the auto advance mechanism from my press for I don't reload large quantities. I do it in batches so in my case I don't need the auto indexing, I just rotate the turret manually when I want to use another die.
Manual or automatic, the rotation of the turret is smooth. The die/ram alignment is good in my opinion. The turret itself is made of aluminum. The top of the press is steel. Actually all metal parts are either steel or iron except for the turret and the shaft of the auto advance mechanism, which are aluminum.
I can't say if the aluminum turret will wear quickly if you use the press in "semi-progressive" mode. I just don't use it that way so I can't tell.
The turret has a little bit of vertical play, but that has not caused me any problem. I have used it for seating bullets, and seating depth has been consistent.
Changing turret heads is very easy. I reload for two caliber and have two turret heads ready with all the dies. I believe I paid around $10 for the extra turret head. I got it from either Midway or Midsouth, not quite sure.
I had the opportunity to compare the Lee Classic Turret and the Lyman Turret presses side by side at a Cabela's store before I bought the Lee. Nothing against the Lyman, but I chose the Lee press for it has a positive stop for the upstroke. I also liked the fact that turrets are easier to replace on the Lee press. The ram is hollow and it comes with a plastic hose that attaches to the bottom of the ram to catch the spend primers. That is a nice feature in my opinion.
Lee makes a smaller turret press but I have no first hand experience with that one. However it's my understanding the smaller turret press has a lot more aluminum parts, and is not as sturdy as the Classic Turret press.
Marc