Am very new to having 2 children as DS2 is only 8 weeks old - DS1 is 2.6 so there is a 2.4 year age gap.
Tbh, contrary to a lot of these posts, I have found it incredibly difficult and probably harder than going from 0 to 1.
But, I think that is all due to DS1's personality - he is a very boisterous, lively little boy who needs constant entertaining. We realised VERY early on that we couldn't leave him alone with DS2, as although he clearly loves him, he is quite rough with him as he doesn't understand the concept of a baby - so DS2 now 'lives' in a travel cot when DS1 is around!! Fortunately DS1 has not shown any jealousy - is quite happy when I am feeding DS2, doesn't mind that DS2 stays downstairs when he goes to bed and that he sleeps in our room etc so I think we have been lucky that way. It literally is because DS1 is so full-on.... but I know it will be worth it in 12 months time when they can play together!
As another poster has said, I am only coping because DS1 is still in nursery the 4 days that he has always been whilst I was working - this means I get 4 lovely days to focus on DS2 and this means that I don't feel as guilty about leaving him in the travel cot at weekends etc when DS1 is around.
There are a few of us on my PN thread who all had children the same age - and we have all found it incredibly hard - but, the common theme is that they were all boys... I wonder if girls adjust better??
I think the hardest thing was that I actually started to resent DS1 for not dealing with it better (what did I expect in a 2 year old ) and not allowing me to love and spend the time I wanted to with DS2....but 8 weeks on, it is getting gradually easier - more of a one step forward, 2 steps backwards thing though.