whats the practical difference between the two? as i understand it the G3 is more modern but is it necessarily better or no?
The G3 was created by the Germans so that they didn't have to buy weapons from other countries or have to rely on US aid.
Plus the FN Fal came out in 1954 and the G3 came out in 1959. Plus this was the earliest G3 which you might recognize as the Fallout 3 assault rifle:

They both started off as battle rifles that shot 7.62x51mm NATO, both had wooden bits and both were improved upon over time. They are both good rifles, however I'd say whether or not they are good comes down to user preference such as ergonomics and ease of maintenance.
Prior to 1955 the two Germanys were not allowed to have any military or an arms industry. They only had border police which were heavily militarized. The BGS was equipped with armored cars and used the FN Fal. They were expected to watch over the East German border as well as the border with Czechoslovakia.
However in 1955 and 1956 the two Germanys had their militaries reactivated and they were supplied by their occupiers. The West Germans were trained by the US military and given old ww2 equipment from the army. However since they were allowed a military, their arms industry was reactivated. So with the ability to make weapons, they decided to make the G3. Plus they didn't have to purchase a to manufacture the FN Fal or have to rely completely on foreign aid.
Soviet and Russian Rifles:
I have some gripes with these rifles.
The first being the AK47 and that is with the name and caliber it fires. The AK47 as it was known was only labeled that until 1959. Around 1959 most of the design flaws and manufacturing difficulties were removed and the rifle was renamed to AKM.
Right around the 70s the USSR adopted the AK-74 which was and still technically is the main rifle used by the Russian Army. Yet the 74 and AKM are always misidentified as the AK-47. Another thing is that people praise the 7.62x39mm for being slightly larger than the 5.56mm round, yet the 74 using the small 5.45x39mm round.
These are also bit too over glorified as being reliable and indestructible. They are reliable, but no as indestructible people claim.
It's hilarious to watch everyone rage when you even mention a railgun in threads like these.
Magnetically propelled projectiles is the future!