It is a bit expensive but I'm surprised nobody else here has sprung for one. I'm not the only one around here who likes their toys.
Reasons why I don't like my refractometer:
- it's annoying to have to squint through it and try to figure out where the stupid line is
- often gets bubbles and I have to wipe and take a new sample
- often don't have a bright point light source handy (especially when the halide is off)
- frequently gets off and needs recalibration
Since it's one of the most frequent things I do on my tank, it seems worth it to spend a little more to make life easier. That said, I asked on RC and the word is that this isn't all that accurate. They recommend conductivity meters, which are more expensive, but might still be worth it to me if it's something I use frequently for years.
I had a PinPoint conductivity meter once, but it got wet and shorted out. So I definitely want something waterproof too.