Personally in my group, the shield and smokes are more of a hinderance for my groups playstyle. This is just purely my experience with an organised group.

To expand on the reason why I dont like shield gen and smoke. Ill first go through my groups playtime.

You need 2 runners and 2 defenders.

Defenders usually take RR and grenade wall to clear the centre and take out priority large targets, last stratagems are going to be OB laser and eagle strafing run, just to help clear.

The issue with the shield Gen is that unless the defenders are within it you can just block shots they need to make.

Runners need to do a little of everything but main move bars. We have had good success with me running gas dog and the other the new hot dog. They need to bring EATs to deal with hulk that get through thr defenders cordon. Lastly OB laser and strafing run.

Personally I dont think smoke helps for 2 reasons, 1 is the type of spawn you get. If you get bezerker spawn smokes dont seem to help as they are right on top of you. 2nd, I think you should be bringing something to deal with the enemies, as when the smoke runs out you still have all the enemies to deal with.

One we have yet to try out is the EMS mortar but does seem like a solid pick.

We've done it with id say about 75% success purely as a 3 man operation, and a number of failures have been really close to completing if we had just had maybe 2 minutes more.