Rampant: This was my first full auto experience and while extremely fun it would be extremely expensive for me.
I can't really compare it to anything else. We actually rented the guns at a range in Vegas.
I've always admired the G3 from the 17 years I lived in El Salvador and saw it in action both with the military and the rebels. The .308 was impressive and I always wanted to shoot it so when the opportunity presented itself i took advantage. I've seen the G3 (or variant) for sale in semi auto before and now that I've shot it, will probably put it on the list of "want to get at some point".
Shotgun: I dearly wish the gun would have had a three round burst but it was semi or full. I shot 7 of 20 rounds semi then went to full auto. It ripped the next 12 in quick succession and rocked me back faster and harder than expected. I'm a whopping 168 lbs so it was inevitable.
Unfortunately I don't have a license to own full auto but after that experience I'm definitely going to see about renting them some more. Might go with a smaller caliber next time.