I've noticed since I changed to 6max theres generally alot more fish.
You Have to play more hands and deal with alot more marginal situations.
People say dipping into 6max is good for your fullring game as you have to get used to playing against people with wider ranges.
I've only played about 50k hands, 10k of which have been at 6max. I like 6max alot better, as there are more opportunities to isolate players and be very aggresive in position.
But also it has higher variance...

Theres my 2cents.