Own several. Don't spend too much. I bought mine from woot.com at ~$50. They are not snake oil. They very slightly magnify. If you use eye drops working in front of a monitor, they do help.
However, I ended up using mine as driving glasses. They are perfect! Unlike sunglasses which darken and cause your pupils to dialate letting more UV light through and arguably your visibility to actually reduce, these filter out blue light (just like Blue-Blockers) which DOES reduce glare within your eyes and they also do not dialate your eyes. You still will end up using your car visor to block out the sun when applicable, but that is the right thing to do.
I only wish that they are polarized, further reducing glare, but oh well. They designed these from monitor use, not driving... but they are nearly perfect for driving.