Another with a large age gap. DS1 is about to turn 11, and DS2 is 10 weeks.
It's fab. Truly fabulous. If I had my time again, I'd of had the following age gaps: 3 years between first 2, and then an 8-9 year gap and have another 2 with 3 years between. 
I'm going to have a third, with a 3.5 year age gap, all being well.
But there has been no negatives as far as I can see from having a big age gap. I'm still sad I didn't give DS1 a sibling sooner. But no problems with the actual gap.
He's fantastic, despite saying he didn't want to do nappies, he has been pestering to do them! The only thing I don't let him do is feed the baby, as he is a bit windy at times, and can vomit feeds, so don't want DS to have that responsibility. But he's a brilliant helper, dressing his brother, carry and fetching. He had a bath with the baby this weekend! He even warms feeds up for me. I miss him when he's at school. Sometimes I think he is a better help than DP.
I say go for it! The way I see it is, I'd rather regret something I'd done, than regret not doing it at all. 