I use a Sunlu S2 but I’m on the edge about recommending it. It works great, if you mange it. Personally, I would suggest buying one that can dry at temps up to 70C, however 80C would be best for some nylons and PCs, but 70C is serviceable. Another feature I think is needed is the ability to evacuate the moisture it pulls out of the filament. This is where the Sunlu S2 comes up short. I have to constantly open the lid, or use a small prop to lift the cover by a few mm’s.
Other features that come in handy are automatic timers and presets for different filament drying. One other thing I think the Sunlu comes up short in is the angle of the print opening for drying while printing. The port is just in a weird position. Its just not good for brittle filaments because the awkward angle. This is pretty easy to eyeball if you are looking for it. As referenced below, the red shows the approximate odd angle for full rolls (which isn’t too bad for low rolls). I got around this problem by using a piece of PTFE tube in the port (which appears to be exactly the right size for that, so they likely intended this, but didn’t tell the buyers). This tube allows the filament to bend at a more friendly radius.
So long story short, the Sunlu S2 dryer is good, but requires more user input than it should.