Someone else also said that they felt that using the HEV chargers wasn't worth the risk of getting hit in the back. I think both these comments show how little people realize the importance of shields. They are in the game for a reason. People need to take advantage of them if they want to survive a hit from any of the more powerful weapons. Charging up is dangerous, but unless the game is really really crowded you can usually find a quiet charger somewhere.
Most maps also have some shields packs lying on the ground for ya, as well.
I know it did for me, at least. People may think that because they always get killed with the egon that HL doesn't have balanced weapons, but I think people should be open to the possibility that they get killed with the egon because they simply haven't learned how to deal with it yet. When I first started playing I though the egon was the most powerful weapon, and I used it as much as possible, but now I find myself using the less powerful but much more versatile MP5 and the gauss a lot more than the egon. I urge those who have problems with HL's weapon balance to keep playing until they see the glory of the promised land that is Half-Life deathmatch. If you sit eternally in the turrets on double cross or crossfire you would unquestionably be a camper, just racking up kills with a massive blast radius, so there is no kill attributed to you.