The GMs we have tend to say they are realistic, and that they put "appropriate opposition". Once a dice is rolled, the result is here and nothing except spending/burning edge can prevent it. One GM also decided that every single NPC should have Edge, because "that attribute is way too broken". Sometimes, it means plays will indeed be tough, other times, it will result in milk runs that weren't supposed to be.
Yes, he decided that my technomancer had a dead only bounty on her head. During the previous run, she had pissed a security rigger/decker from KE because she had resisted without a flinch every single data spike he had launched at her. Somehow he managed to get some info on her - including street name - and used 25k nuyen from his own pocket to put the bounty. The two players who decided to take the bounty were weird ones : one was some sort of prototype with 6 cyber-arms and a weird view on the world, the other was an Oni fighter who had the bad habit to act first and think when harm was already done.
As an excuse for the GM, it must be said that when he told those two that there was a bounty on my head, he never thought even an instant that they would try and kill me.
So, I was talking about milk runs that shouldn't be before. Because of some events, one of the Draco Foundation's team (the one that basically replaced Assets, inc after it disbanded in our GM setting) was in our sprawl (which is Sydney), and one Johnson wanted them dead. Reward was 20k per head, which was huge for us. There was a lot of hesitation, but we decided to give it a try. We chose to attack when most of their linked spirits were away chasing that one guy they were after in the city. We had the help of a headcase melee adept that worked for our johnson, and we charged the building the ennemy were in with an autocar, while our decker helped by a technomancer we hired attacked together the ennemy team's decker that was in the UCAS (they were supposed to hack her, get her localization, give it to our johnson and then brick her and come back to help us).
Well, to sum it up, let's just say that right now at our table, there are now 6 players with the "tough and targeted" quality that didn't have it prior to the run. No casualties on our end, besides two rotodrones. The GM told us after that every single guy in front of us were better than us in every possible way. What helped us was the good use of small unit tactic, and the fact that they didn't take us seriously immediately. By the time they did, their heavy armored drake was possessed by one of our cabalistic mage's spirits, and the headcase had found the ennemy rigger and cut him in half.
But I must admit that one run was a huge exception for me, so I'm partially surprised to read you, Raphael. For me, it sometimes feels like the GM would find a way to use our team as cannon fodder so the NPC he created for the campaign would be kept alive.