I've purchased Ranktracker, BIQ, Serpwatch, Nozzle, and Ubersuggest.

I have to say it's a tossup between Nozzle and RankTracker.

!!**One thing for other sumo-lings is RankTracker has incentivized reviews (which is fine by me - partly why I am leaving this review - It's still a great rank tracking software. Just going by total review count is not in your best interest. Purchase both, try both, take advantage of the 60 day return policy**!!

Nozzle has a unique feature set with tracking using pixels from the top which is a different but important metric for any webmaster / SEO to know. Google is more complicated with FAQs, People also ask, rich snippets, image carousel, and videos. Knowing how far from the top of SERP your listing is can be more valuable than just knowing your position #3. Nozzle also gives 21,000 keyword checks so you can exceed 1000 KWs if you set the check-frequency to once a week or month. I also had an issue with account creation, support is very friendly and responsive. Tanner even got on a video call for 20 minutes to help me out.

Serpwatch has a good clean UI/UX but I've held this for a year or so now. Their development seems slower. Some features they released like KW research also require you to upgrade the plan. I refunded my recent 3 code stack for RankTracker.

RankTracker may have a slight advantage over these other deals for Sumo-lings. The exact match domain + the recent AppSumo promotion I believe has increased their search for branded terms and will likely allow them to continue to dominate for the term "Rank Tracker" in Google (they now climbed to #1 in google for Rank Tracker). This will probably help the long-term sustainability of the company and getting grand-fathered in with this LTD may pay off.

Other than that - I found it easy to use and navigate. Other things I liked:

👍 Site Audit feature with suggestions and SEO checklist
👍 Serp check to see current results in different countries
👍 KW research + creating a KW list
👍 Unlimited users
👍 Automate reporting

Cons:
👎 I prefer the flexibility to have KW checks and set my own frequency.
👎 Sometimes can take up to 30 seconds to fetch the SERP features while researching individual KWs. Wish it was a little faster.
👎 No backlink data (maybe not a fair criticism against a Ranktracker - but to win against Mangools or Ubersuggest for lower-end SEO tools compared to Semrush or Ahrefs having some backlink database would be nice).