I have to agree with ebzed here. You get some great service and some poor service (and I say this as a 'lowly' PL, nowhere near TPL). However, I ALWAYS make a point of sending EL AL's customer relations feedback, whether the service was particularly good or whether it was particularly bad. No business will ever improve without feedback, and for those of us who are pretty much tied to EL AL for our own reasons (flight schedule convenience, or whatever) we all have a vested interest in giving as much feedback as possible.
One example which I have posted here before (I think) is the appalling state of the SKML in First from Israel (and also returning from London) until 18 months ago. The food was so bad that the crew always apologised to me for it. I almost 'terrorised' Haim Romano about it, sending printed photos by registered mail, cutting up my PL card and my wife's GL card and sending them with the photos in the envelope, etc, etc. Without belaboring the point, it didn't take more than a month before they arranged for me to visit the catering company in Netanya, which resulted in my sending them a report. 6 weeks later things began to change, and a month or so later saw the whole thing completely changed, and the food and presentation at a perfectly acceptable standard (although still not nearly as good as Hermolis, but they can't afford that).
But it is vitally important to give them feedback if service is particularly good as well as to complain if it is bad. That way the better employees get encouraged and the whole picture gets better.