I use a friend's 24" drum sander with power feed, and it gives really nice results. I don't really recall what brand it is, but it was expensive ... so Ican't really recommend any brands. I will point out that in drum sanders power rules and you may be limited with a small low power unit. As for the $1000-1200 smaller 10" benchtop units like Jet and similar makers, they are a waste of money. Read the reviews and you will see that few people had any luck with these. If buying used, you really need to know why they are getting rid of it. Estate sales are the best deals because they want to get rid of a huge heavy machine that has only a few people wanting one.
The main tip I will offer is to make a sanding "tray" to set the blocks on. Mine is a sheet of 3/4" plywood with 1/2" lips on all sides so I can run it through in any direction. Set the blocks in the tray with the ends resting against the lip. You can fill a tray with blocks as long as the first row is against the lip. Run the whole tray through the sander repeatedly as you lower the drum. Once one side is sanded evenly, flip all the blocks/scales and do the other side. This makes absolutely even thickness blocks or scales.
Second tip is - Get a good size dust-vac system just for the woodworking tools and the drum sander. It creates a LOT of dust, and you have to suck it away into a bag. Don't forget to dump the bag often. A drum sander probably needs a 2HP dust vac.
Third tip is to get a 6X36 or 6X48 belt sander to do the sides and refine the tops/bottoms. I have used a variety of belts and found that 120 grit works for cleaning up the sides and flats to get the wood ready for a spray lacquer coat. Belt changes are fast, so coarser roughing followed by as fine as you need is easy to do. When I don't have time or a large batch to take to my friend's shop, I use the 6X48 to do all block sanding. I have probably processed 1000's of blocks on my 6X48 Jet sander and recommend that brand. It has a 9"disc on the side which is also nice for a last touch-up at a fine grit. If I was making te purchase again I would get the larger/heavier professional model with the 12" disc.
These sanders can be found used for pretty cheap. New 6X48 220V professional grade units with a 12" disc run $1500-2000. The home shop 6X36" with a 9" disc units are around $500-1000. When I bought mine 20 years or more ago it was around $300. As for HF and similar places - You usually get what you pay for. I have seen the lower priced Rikon units at Woodcraft, but don't know anyone who has used one so I don't know how they last.
