Pros: Affordable, accurate, no messy test strips. Customized instructions based on your chemicals.
Cons: Sensor is big, cold water messes up the readings.
We bought a house with an inground pool about a year ago. Pool newbies, no clue how to manage the chemistry. At that time, the Aqua Vizor was going for $400, a little out of our price range. So we bought test strips and went to pool school. Last spring the price went down to $250, so I bought one. At first we double-checked every reading with the test strips. But it was always spot-on! And its recommendations for how much of which chemical always brought the water to optimum levels. I especially like how it notices trends and recommends chemicals before they get so drastic. Small adjustments seem to make it need less attention.
Its super-easy, convenient, and no-messy test strips.
The disadvantages - the floating sensor is BIG, that surprised me. About the size of a small trolling motor. And it does tend to get banged against the wall by the Polaris and swimmers/divers. You definitely have to take it out for pool parties. Cold weather seems to freak it out. Once the pool water got below 68, its been giving weird readings. I guess I'll take it out for winter.