Upgrading from my Trophy to the Lumia 710 provided such a massive difference in web browsing and gaming at the top of the improvements. I had been thinking games due to xna scripting were just doomed to be slow on WP7 devices. but they run great on the second gen phone. Unplayable jerky messes to perfectly smooth. Was not expecting it.
Likewise, internet is also more than twice as fast as the old phone ,on the Lumia. So the jump from your Focus to OneX is probably a testament to just how underpowered those gen1 WP devices are nowadays. You don't notice the slow speeds till you get faster, because even running slowly everything is nice and smooth for the most part.
I will say that my Lumia was slaughtering an apparently much more powerful Photon 4g that my cousin had over the other day. Bested it in everything.
So it is some specs. Some software, but IE on Lumia is fast too, and some just new gadget goggles, We all get those!! Lol
Rock on and have fun with new phone, you will be back....!