...on my 18" Enco band saw. It's a low-end Taiwanese saw that I picked up new for $300, from someone who bought it but never even wired a plug onto it (It's a 120/240V saw). The guides that came with it were standard blocks, but they were a real pain to adjust and wore quickly. The Carter guides are a huge improvement and they control the blades much better than the blocks did. My primary use for this saw is re-sawing raw oak for ribs and other rough cutting duties, and it has a 1" wide blade on it. The bearings are perfect for this application.

I also have a Craftsman 10" band saw (made by Rikon) that came with roller bearings. Again, I like them much better than blocks. Here's my take on the bearing vs. block debate.

- While blocks have much more contact surface, it's largely irrelevant. The main purpose of guides is to prevent the blade from twisting or deflecting side to side. For that, the only thing that matters is how much of the blade WIDTH they support; the amount of blade length contact doesn't matter. Bearing guides with double bearings support at least 1/2" of the blade width, which is as much or more than most blocks do

- Blocks are great when they're new, flat and adjusted close. However, they wear quickly and allow the blade to move. Moreover, they tend to wear unevenly, mostly at the front, which prevents adjusting them tighter since they will bind on the back of the blade. You may be able to get around some of this by rotating the blocks 90 degrees or grinding them flat periodically, but it's an ongoing battle. Bearings don't suffer from this type of wear problem.

- Bearings are not a panacea. As others have mentioned, most bearings used in band saw guides are not very high quality. Particularly when used with narrow blades where only on bearing supports the blade on each side, the most important criteria for a bearing is that it has no play in it, otherwise it will allow the blade to wobble, just like worn blocks do. The bearings in the Carter guides do have enough play in them that they could be problematic with narrow blades.

I will probably replace the stock Carter bearings (at least the front pair) with higher-quality, deep-groove bearings. More than likely, I'll use full-compliment Enduro Max bearings. They're marketed to the cycling industry, but I suspect they'll work great on band saws. The #608 bearings which would fit my Carter guides are only $3.00 each. http://www.enduroforkseals.com/id169.html

I have also used bearings from VXB Bearings for several applications around the shop. They have a wide variety of sizes and types, from low quality carbon-steel shielded bearings to full ceramics at reasonable prices. They carry sealed replacements for the #626 shielded bearings on my 10" saw, though the current bearings are tight and I probably won't replace them soon. http://www.vxb.com/Merchant2/merchant.mvc

It may be possible to find needle roller bearings or double-row bearings that will work on Carter guides. Their width would ensure that they cannot wobble, so I may explore that alternative. If I find anything interesting, I'll post it here.