Insanely good, if overwhelming at first
For reference, I was using BiQ (awful) and SerpWatch (pretty good, but basic) before Nozzle.
Nozzle has an insane amount of data that is really useful if you want to keep track of your search engine rankings, and then be able to come up with a plan of action for your site(s). Pretty much anything you can think of tracking is available, and it's all customisable to show what you are interested in.
I would say - if you are interested in something quick and easy to see your rankings, maybe stick to something like SerpWatch, where the UI is very clean and clear. But, if you want deep data, then Nozzle is definitely for you. SerpWatch comes nowhere even close to Nozzle in that regard. Don't even bother with BiQ, which is really poor.
Nozzle also allows you to track competitors for free, which is really great.
The one thing I wish Nozzle had is a "basic mode", to see quick and easy data. But I would take the in-depth nature of Nozzle over a more simple platform any day of the week, even if it does take me a while to get my head around it all.
If you spend some time with Nozzle, it does become more obvious in how it works, and I would recommend doing that because the product is really fantastic.
And just to cap it off, the support is excellent. All my questions have been answered within minutes by Boyd or Derek. This gives me confidence for the future of the platform.
Definitely 5 Tacos and a full-stack from me.