Maybe little late but mineral oil if it revs max 8000rpm , 8000-12000rpm semi synthetic , fully synthetic only for 12000 + rpm, if you use oil that your engine needs it will last much longer, instead of putting fully synthetic on 50cc or other engines that dont rev above 12k you just shorten its life span. As for brands i would say ipone,elf firstly& castrol, also premix 2-3% max on liter.
My personal experience is that too. I mean you can run good branded 2t mineral oil fine, but most places don't even sell it... But I've rebuilt loads of motors that have ran on biltema oil....
Its not better , i mean in quality and other stuff yes, but you cant use a fully synthetnic oil on a engine that revs below 12k rpm, the enigne wont run good it doesnt burn the oil at all, you get deposits left everywhere. Most of the people dont know this and they just use fully synthetic oil on 50cc all the time like nobrainers, its funny here in my country.