Yes, absence of the right to keep and bear arms is a dealbreaker.
If that's dealbreaker, then yes, the US might be one of the only places in the world where that currently stands. I am not so confident that it stands into the future as various states have been chipping away at those rights. I think that in time, the right will be essentially meaningless compared to most other first-world countries. But that's for another discussion.
However, in addition to the rights “guaranteed” by the amendments to the constitution, there are the actual and tangible conditions that exist in the USA one is free to enjoy. For instance, it would be difficult to find the quality and variety of foodstuffs, fuel and clothing at the prices that we enjoy, anywhere else in the world. The reliability of the electrical grid and quality of the municipal water supply. The efficiency and excellence of first responders, and many more. Music, sports, highway system and national parks, etc. I have lived outside the US in 1st 2nd and 3rd world countries. I have never seen any place that brings it all together for me like we do. I suppose it depends on ones priorities. God bless America!
I would argue that there are plenty of other places in the world where those conditions are met or exceeded.
Let's take the electrical grid, for example. In the last 50-60 years there have been major blackouts that covered vast portions of the US. In California, parts of the grid had to be shut down last year either to prevent or because of the fires. Puerto Rico is a US possession - their grid hasn't recovered from the hurricane. Heck even locally there are issues: I've clocked an average of a full day of downtime per year at my house (major metro) due to storms and lack of line maintenance.
For water, we can look to Flint. Other infrastructure? I've had 6-10 hour internet outages (and I put 25-50% packet loss into that category) the past couple of days, and average 1-3 days a year of total crap service. In my metro, the roads/highway system is a mixed bag and far below the potential - likewise rail service.
And so forth. Nothing on your list cannot be provided by a NON-CORRUPT socialist country - and it's the promise that's been made in communist countries (though generally unmet).
The US certainly has the ability to provide all those conditions. Many places either don't or limit them substantially.
But as you said, it depends on what you value. I am glad to be in the US, but I've also seen it's flaws. Whether those flaws affect my retirement home is yet to be answered - certainly I've already decided that there are a number of states here in the US where I will not retire.