I purchased 2 sets of these derailleur pulleys. One set had loose bearings. I corrected that by loctite and steaking. The other set was ok. Function is good and driveline runs quiet.

Stylish upgrade, seems to be a quality product. I will update after 6 months

This jockey wheel fits good and looks nice. It does have a sealed bearing. I can't say I feel a difference but a bearing is better than a bushing.

Update:
The seller contacted me and said they had revised the jockey wheels, and wanted to send me a new set that would work. I said "sounds good", and they arrived last week. I installed them and took my first ride yesterday. They worked great. Nice looking, quiet and no chain suck. The bearings seem to come dry (dryish?) so make sure you get some lube in there before you install them. Otherwise, I'm very happy and good job on the sellers part to reach out and make it right. Rating revised to 4 stars.
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Update:
I found another review here, with a video, and the guy had the same problem as me. These are NOT compatible with narrow chains on high count cassettes (in my case a 9x). The seller should make this clear. Down to one star.
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I bought these about a year ago and finally just installed them. They look great and the quality seems good, but they're grabbing the chain as it goes by, so I put my old ones back on. I just rebuilt the drivetrain, so the chain is brand new. Maybe they'd wear into the chain if I gave them a short ride, but I don't want to risk damaging the new chain doing that. There are a lot of good reviews here, so I'm unsure why I'm having a problem. I have a Shimano 3x9 gearing mountain bike. Maybe with narrower chains (for use in 9 wide cassettes), this part is too wide and jams into the chain. Anyhow, beware.

Easy to install and perfect fit. I used locktite to prevent loosing and falling off. The color finished rubbed off very quickly by the chain which was disappointing for me. With over 300 miles ridden, so far so good.