It all comes down to doctrines when playing this game and less about micro or strategy. So far, the shock frontline seems to be the most used and / abused doc, offering abilities against every unit which are supposed to counter its broken Call-Ins. Though it is understandable as the SU stock units are average (ie not OP) so it is the best decision to go with it. Examples ('top' 100 players) :
Since you clearly stated it's you who is having issues playing as USF then starting the thread on the strat section would have been better.
By the time your opponent starts rolling out KoenigsTigers (WTF) you should have 3x 57s and 2-3 jacksons. Use the p47 to make sure it won't make it back home.
You pay for tier 3 it unlocks and not unlocks and it will say sorry we cant build it agains because you already build it , but you cant make units from it :/
Well it doesn't say sorry. And yes, the glider is not causing this from my experience as well.
Being an immobile version of PM41 and therefore extremely vulnerable, it should be much cheaper than it is now. I think it is not just me and others share the same sentiment. Furthermore it's kinda the only support brits have in game.
There should be an incentive to build it and currently there is none, other than losing 400 MP to infernos, lelIG and basically anything.