It's a great place, for sure. And I am not only talking about Beirut but also the rest of the country.
Your main concerns should be
1) security
2) job
3) budget
1) The security changes almost on daily basis, however the locals are very well informed & rarely something happens without people knowing in advance and telling you. Networking with people from different communities is essential.
2) It's not easy to get a job & residency in Lebanon as a foreigner. Be aware that most Lebanese are multilingual starting to learn Arabic, English, French, Armenian and other languages from the cradle onwards. Private education is normally done in English and French only, which explains a lot. My best guess is that Lebanese private schools would not hire foreigners unless there is a specific shortage or demand - I do not have evidence for this statement but could imagine it is like that, having been there many times. Lebanese are highly qualified and this should also extend to teaching. Also, the visa process is fairly complicated for employers and salaries for expats too high compared to Lebanese. I was interviewed in Lebanon by a friend and she told me that despite all my qualifications, she could not offer a good salary, did not want to go through the painful and costly visa process, and then have someone in the company who 'only speaks 3 languages fluently' (Arabic not being one of them).
3) Lebanon is not a cheap country, and you would need at least 700$ a month if you find a cheap place to rent and do not party & travel too much. The average salary in Lebanon will not allow you to put money aside.
Now, after all this, I can imagine it would be a fantastic experience to live there and get to know the vibe of this city and country. It's a great place to be, a great place to gather experience, and have a good time.