My wife and I have reached the age where reading glasses always have to be at-hand, and I still have a hard time seeing small details. She had a smaller 75mm cheap plastic hand magnifier which was not very effective. The reason is that it is just a bit too small to see well with both eyes, and there is a lot of distortion around the edges. Then there is the incessant glare from the ambient lights.
I bought her the 6 diopter 100mm aspheric magnifier, and the clarity is stunning. This is an excellent size for use as a general-purpose magnifier for looking at maps, reading the fine-print etc. Probably not strong enough for a stamp-collector or that kind of application. But there is of course a tradeoff - the stronger magnification comes at the expense of diameter, and she is happy with this size. So much so, that we bought two more for presents!
The anti-reflective coating is very effective - glad I opted for it, it makes a big difference.
Yes it is probably the most expensive magnifier out there, but given how much use it gets, and the superb manufacturing and optical quality, I do not regret paying this much for a magnifying glass.
Pros: Top-of-the-line optics
Cons: Very expensive
This review was written in the old system and had content requirements that are different than reviews written today.