What faction do you play?

I play Retribution of Scryah and my wife plays cryx for warmachine. For hordes I play legion of everblight which my wife is thinking of taking off my hands.. so I may go to trollbloods next...

Isn't Warmachine and Hordes the same game?

Yeah they have the same mechanics... the only differences is warmachine you have your leader as a warcaster which has focus points that regenerate every turn to the max focus on your warcaster which the warcaster can allocate to jacks, use for spells, boosting its own hits, damage, running etc and your heavy lifters is warmachines called warjacks which are steam powered golems which you have to use a point of focus to do power attacks, boost an attack, charges, running, special abilities for the jacks, etc uses up a focus point and your caster has limited focus for spells and doing this. In hordes instead of warcasters they are called warlocks and they use fury instead of focus. The only way to regenerate fury is to leech it off of warbeasts which replace the roll of warjacks in your army for hordes. The only way to generate fury on beasts is to force them to run, boost an attack, charge, power attacks, extra attacks, etc each makes a fury on the warbeast your forcing up to the max fury they can have. Also warbeasts have animi which are extra spells that are derived from the warbeast kinda like additions for your warlocks spell book. The only way to use animi is to add fury equal to the cost of the animi to the warbeast so your limited on that as well. If you don't leech off all the fury on a warbeast at the beginning of your turn then you have to roll to see if it goes bezerk and attacks the nearest model to this warbeast that fails. Your warlock can discard any extra fury he/she has left at the end of its turn.

There are loop holes in the game around to leech farthur fury off warbeasts and to add focus on your jacks as well. Each faction has some way of doing this.
That's why in warmachine it's called focus management. In Hordes it's called risk management lol.

Is it the same game? Can a warmachine army play a horde army?

yes they can play against each other. They have the same mechanics, but only have the differences I stated above... Also different than warhammer the game is supposed to be played on a 4 foot by 4 foot table.