I have 8 years between my boys. Going back to pregnancy and babyhood was better than the first time round, so didn’t feel too much like a return to anything bad. DS1 was initially upset, but came round well before the birth.
We haven't found entertaining them tricky either. DS1 in some ways revisited his 'only child' childhood, and we tend to do fairly age-neutral activities anyway, like trips to the beach or walks. Otherwise, we'd divide and conquer, but this naturally (happily!) happened along the lines of mine and DH's interests (one sporty child, one more arty).
The boys adore each other. At 11 and 19, both are old enough to be on the same wavelength and now enjoy each other's company.
They're both our children, so regardless of the age gap, there are certain things they'll always have in common - the same sense of humour, the shared memories, the in-jokes at mum and dad's expense...
Eldest is now at uni, but comes home regularly (my only other regret is that sometimes I feel he's making up for lost time, sibling-wise) and they slip into their old ways.
This stage has been the hardest for me, though, in terms of DS2 flying the nest being so far in the future and going back to having, to some degree, an only child - lots of people seem to think that's a good thing though!
Obviously I have nothing to compare it to, but this age gap has worked well for us. While in some ways I wish I'd had them a bit closer together, maybe 5 years instead of 8, I am glad that we did get round to it in the end, rather than letting the age gap put us off.