They are more rare than 25 stat signet.
Compared to cows still, cows are way better imo. You get 900k exp from a solo run with exp pots. It can be done extremely fast, easily sub 1min run.
By the time you clear torajan jungle.. backtracking, and smaller signets are realistically worth as much as just packs of monsters.
This area still has decent overall exp, but imo it might be even worse than TA in average. I leveled to 121 this season in ta, and running route through 3 big rooms, popping 2 exp potions i was getting 600k. Significantly worse than cows, but you get really decent unique drop (way better than jungle).