Apologies if this has already been answered somewhere else. My macbook pro is on its way out and I'm considering switching to Imac. I intend to use it mainly for work with illustrator, photoshop and indesign (potentially more in the future). It was recommended to me in the apple store that I upgrade to 256GB Flash Storage as it will improve the performance when using programmes such as these. I'm always a little wary of taking advice from shop workers as my knowledge on this kind of stuff is very limited so I'm looking for an unbiased opinion. Also, is there much difference between the 21.5" and 27" besides the obvious (this coming from someone who still doesn't even understand what RAM is). and are the differences important for what I want to use it for. Again, sorry if this has all already been answered.