Brix Meter (refractometer)

Has anyone used a brix meter as part of their grow?

Also known a refractometer (or reflectometer?) , a brix meter measures the sugar content of plant tissue. It has a prism on one end and an eyepiece on the other. When a drop of sap or juice is viewed through the meter a reading is given that indicates dissolved solids in the plant's system. This can give a much better picture of plant health than guesswork based on how the foliage looks etc. as well as alerting the grower to deficiencies or toxicities in the soil/medium/water.
I think they can also be used to assess ripeness, as I originally heard of them in the context of wine-making (although perhaps sugar levels can't be used to gauge ripeness in Cannabis as it is in grape vines.)

The meter isn't terribly expensive, around $100 for a Milwaukee.

Has anyone had any experience with these?

A couple links:

Brix - Wikipedia, the free encyclopedia

The Brix Meter explained - General Hydroponics - Indoor Hydroponic Gardening, Hobby Gardening, Hydroponics System and Hydroponics Experiments

http://www.extech.com/instrument/products/alpha/manuals/RF10_15_UM.pdf
[Instruction manual for an extech brix meter, shows the usage procedure and the kind of data collected.]

The Growing Edge Magazine - Gadgets and Gear for Hi-Tech Hydroponics
[this is a crazy article that will make you wish you could print money. The brix meters are mentioned towards the end.]

Marijuana Growing: Indoor Gardening : Recent Innovations in Growroom Technology
Cervantes article, mentions Brix meters.

Brix Refractometer - Hydroponics Forum - GardenWeb
[random forum discussion of brix meters]

yeah brix meters are useful when making sure u plants are healthy
a brix reading of 12 means plants are healthy i think it is ill look it up and get back to you on that one
a good investment but not very neccesary a ph meter and a ec/ppm meter deffinately more important but if you got the money get it =)

I use one since 2008 weekly here in my garden, if it broke, I'd have another one before its time to read again. the high reading is nice, but not at harvest, like say, apples. important to me to watch just another health indicator, metabolism, peak harvest time.

I know of a number of growers that utilize a refractometer in their gardening practices on a regular basis. However when they use the tool they are measuring the sap from the leaf juices rather than the stem.

A reading of 12 is basically when the soil or grow medium is just fertile enough to repel pests.

PPM and or PH meters are not used by the gardeners I happen to know.

12 brix does not repel pests. pests love sugars. a brix reading of zero would not interest a bug. my apples are high brix too, the higher they are....the more they're loved by all.
pro mix attracts NO pests, till you add nutrients. The soil will attract bugs, when it is just fertile enough actually.
I use the juice from a crushed leaf to test my brix.

Just for the sake of information... For anyone wondering. I do not need pesticides with the "High brix" organic gardening. If pesticides are still needed the grow medium is not fertile enough.