Iran is one of the friendliest countries in the world, with thousands of years of history and culture, great hospitality, and amazing local food. It is a bit of a treasure trove for the enthusiasts with 727s, old A300s, AN-74s etc. flying every day.
The politics in Iran is certainly complex, and as mentioned before Mahan Air is still subject to various sanctions, but you can still easily fly them domestically. It's interesting that in spite of all the sanctions they have built up a pretty big fleet of A340s.
The US has changed their ESTA rules so a visit to Iran would-in theory mean you need a tourist visa for the States, but a second passport or dual nationality MAY get around that. I can't really find an answer for that. Anyway, if Trump gets in I don't think I'd want to return to the Land of the Free ;-)