The SGC speaks softly but in this universe humanity also has the big stick. You may not approve of the methods, the xenophobia or the militarism but if the blood sucking monsters from outer space ever did turn up, wouldn't you want the gung-ho, shoot first and dissect later, alien technology back-engineering wizards of X-Com on hand to even the score and then rewrite the rules of the game?

X-COM recruited the best personnel they could find, and did so from right around the world from day one. If they coexisted with the SGC and started recruiting certain specialties earlier than Stargate Command they would have likely already got to certain characters first...

With their primarily military perspective and gift for seeking out, back-engineering and then sometimes improving alien technology X-COM would likely be both more effective and creative with technology found in the Stargate Universe than the SGC ever was. They would also likely be paranoid, xenophobic and all to eager to pick a fight.  

X-COM methods would excel in military operations against the Goa'uld, their prospects for diplomatic successes however... not so much.

The introduction of X-COM technology and tactics would gradually alter the way things were done at the SGC but the universe is still going to throw up the same old problems...

X-COM is just a tad more ruthless than the SGC ever was...

The SGC isn't the only base which has to suffer from occasional uninvited extra-terrestrial guests.

Even in a war against two different Alien threats there are lulls in the campaign for the men and women of XSGCOM.

X-COM isn't going to be as accomodating when it comes to allies as the SGC

Some changes in this alternate universe are smaller than others but in the long term they can still be significant.

Familiar faces may crop up earlier than expected.

Philosophical differences on what methods are acceptable are inevitable.

There are worse things out there than Apophis...

X-COM takes the fight to the enemy and Cassie starts to show her true potential.

Diplomacy pays dividends, secrets are revealed and Ba'al schemes

Other human civilisations with advanced technology get suspiciously treated or seriously threatened as the Tau'ri advance.

Ascended Ancients, Kinsey, Ba'al and the Tok'ra... all scheming with their own agendas as the war continues.

Earth bolsters its scientific personnel from unlikely quarters as Apophis learns Anubis has returned.

More advanced technology and weapons means events don't turn out quite the same way in this universe.

Diplomats, spies and fighter pilots, each plays their part as Earth continues to expand its influence.

Not every new technology encountered can be figured out right away.

Slightly different approaches can lead to revised outcomes, some more divergent than others.

The other, "better", SG-1 gets to show what they can do as Anubis and Apophis fight for dominance.

Janet gains an insight into another person she didn't want, Teal'c deals with family business and Daniel discovers meaning of life stuff he doesn't like.

Thor underestimates Anubis and the Tau'ri decide that despicable methods are called for to save him.

Sometimes political machinations and scheming will get you further than machine-guns and soldiering.

SG-1 struggles to find a replacement for Daniel and Anubis comes calling on the SGC with his newly aquired technology

Or how I learned to stop worrying and love the bomb...

Thor returns in a borrowed chariot and everyone wants it.

The Ascended watch and the mortals plan to act.

Spying, war, science, politics... everyone has their talents

Sheppard gets a new toy, Jonas goes home and Janet's insight deepens

Can division between the Tok'ra and Free Jaffa turn to unity?

Earth trades goodwill and technology with its allies in readiness for when markers will be called in. 

SG-1 finally get to meet the next stage in Replicator evolution

The Goa'uld start to improve their tactics as Earth prepares to re-visit some worlds and the Free Jaffa and Tok'ra move towards unity

 Loki regains the initiative while Harry Maybourne retires

SG-1 meets the Hebridan and the Asgard repay a debt

Jonas and Cassie have a revelation, Osiris returns and Prometheus rearranges the map

The fortunes of war swing back and forth as Prometheus continues on its journey

Apophis adapts to new ways of war and Earth reacts in kind

Cassie uses her skills, Anubis finds an ally and Sharp embraces an opportunity

Anubis arrives over Abydos and Daniel... interferes.

 Apophis and Anubis go head to head

 With the Goa'uld threat reduced the time to deal with Loki arrives

X-COM takes the fight to Loki's base on Mars

Daniel returns to the SGC as Loki shifts tactics

The fighting on Langara causes a shift in attitudes 

The Tok'ra/Free Jaffa Alliance prospers, Loki is hunted and Sheppard and Rodney race

 Fun with stargates, the Hak'tyl ask for help and Loki loses and wins some

The Kull Warriors appear to shake things up nicely... or nastily

McKay stops a world blowing up for once and Anubis attacks Earth