I've got a Traeger Junior that's never had it's normal ignitor fail. I used that grill as my sole grill for 4 years... it got used partially for a 5th season, but doesn't get use these days.
It's my understanding, that the worst thing you can do with a ignitor is to turn it on , when the firepot is still hot. Now, for the most part , none of us actually have the ability to control this part of things. However, I personally disable mine on my PG500 sometimes when I cook at really low temperatures ( 170F or bellow ), because it has a 'auto relight' that will take place if the grill thinks it's temperature has droped bellow 140F . The grill can be fooled , thinking the grill is too cool, when you open the doors for long, while cooking at such low temperatures. My PG500 is going on like 4 years old now, still got it's original igniter in it.
As for ceramics... at one point I was under the impression they never fail., but that's apparently not the case. At one point I had seen some Rec Tec users say they had replaced their ceramic igniters with less then 4 years on them...
So, in short... I'm not totally sure ceramic necessarily gets rid of 'quality' problems... and I know that quality must play a big role in longevity of igniters...