I use an Easydens. The price will probably put most people off but I have used it side by side with multiple of Anton Paar's much more expensive DMA 35 units on separate occasions and besides showing less decimal places (although it measures to 4 in SG), it was flawlessly accurate throughout triple brew days. Also, being able to use it as an alcohol meter for pure spirits is very handy if you do any distilling.
The other plus is that like a refractometer, you only need a very small (2ml) sample to to get a measurement, but unlike a refractometer, you dont need to consult any wort correction factor tables to get a true reading.
I am very happy I bought it, but I don't begrudge anybody who balks at the price.