Which gel saddle? Without knowing, I don't think you can get a meaningful answer - and even then, you can only get an answer that's right for someone else.
I had a gel saddle and did lots of long day rides on it... and it really was quite often painful by the end of the day. I'm really not sure why it took me so long to replace it - it's possibly because I was in some sort of denial after having given away my old Brooks B17 with my previous bike.
But others clearly find different and are well suited to their gel saddles.
I don't think it's anything to do with the kind of saddle - after all, 'gel' is just a sort of foam, and people ride foam-padded saddles for very long distances.
It's surely just the individual saddle that counts, and you just have to find one that suits you - be it gel, leather, wood, cheese, whatever.