Three of us left a few days after the Tripoli bomb in August. The roads were a mess as they had some checkpoints here and there, even the crew arrived late. But still managed to get out without an issue.
I think that, in Lebanon, terrorism actually is discriminate - which is exactly why certain locations only are discouraged, with the majority of the country being green on the FCO map. Almost all the time attacks are within the Southern Beirut suburbs or in Tripoli.
I forgot to mention, on the night the TK pilots were kidnapped, I was actually heading to the airport for the 148 - at exactly the same time (and on the 'old' road, where the kidnapping happened). I haven't heard, nor seen, anything, nor knew anything about it until I landed at LHR!
It's your call, but I think that, at this low price, and given that you have the opportunity and plenty of time to plan your time, you should definitely go