I am not by any means an authority on the subject, i only got my mbike learners in 2010. back then i got a 250 mini cruiser (my first love) to learn on. that bike fit me like a glove. it didnt have big grunt and going up long steep hills etc it struggled for sure, but the other 90% of my journey was fantasic as a first bike. peer group pressure saw me buy a 800ccM50 as soon as it was legal for me to do so. it was a big bruiser, big noise big grunt.....but also and extra 100kg. all of a sudden the ease of which i could flick the 250 mbike around tight corners was replaced with a titanic trying to doing a u turn feeling. sure i am not gifted when it comes to riding, but the 'perfect fit' was gone and i wasnt enjoying my rides anymore. i went back to a 250 mini cruiser again, and despite the loss of grunt, i was enjoying the rides again and much more happier. time goes on, more experience and confidance, and i decided to up grade to more grunt, but not as heavy a bike. this time i got it right, grunt, and handling and a good fit. so in summary newbies. enjoy your first bike for as long as you can, and then upgrade. dont rush it.