For many years i've been looking for a spectrum analizer in hardware form that didn't cost a fortune... And here it is!
This is a really really good analyzer, it shows alot of relevant info like frequency response, stereo width and even a cool radar mode. Plus - it measure LUFS and not only db and RMS (like most other does).
The only downside I've found in this is that it doesn't have a dedicated power on/off switch. To power on you just press the button furthest to the right and it is good to go in a couple of seconds. But to power off, you have to hold the same button for three seconds before you put it in a "turn off mode" (since this button is doubling as an edit button as well).
All in all, this is probably the best you will ever find in this pricerange and it really helps to being able to see this info all the time, so you instantly can see if you have phasing issues, unnecessary low-end etc.
One note - if you are planning on using this with anything that has a metering port (d-sub 9 pin or any other d-sub connection) prepare to make your own cable. I'm using an Crane Song Avocet and they were very friendly with providing a schematic for this.