ds was 4yrs 4mtgs when dd was born. I don't think of it as a large gap either. The way I saw it was that as I'm young I would rather spread things out a little as I've got the choice. If I had another (I'm not sure I will) I would want another big age gap.
I can honestly say it's been easy. I worried myself sick during my pregnancy feeling really guilty on ds as we were so close and I felt so bad, but I needn't have worried. I don't remember the newborn bit being difficult (and I'm a single parent - have been since dd was born) I was taking him to school on the Monday after having her on the Friday. It all worked well as I knew as long as I got up and got ds out the house, he was getting his time at school, away from the baby, and I was getting my time with her.
Dd has always been very easy. She just fell into a routine, I think because of school run etc it was the same every day.
She is a lovely toddler, very bright as she's picked up lots from ds. They play very well together and ds is very protective of her. They have their moments (when they gang up on me!) but they don't really fight, I think because ds knows he's that much older and bigger than her.
I would say go for it, definately. I would never chose to have children close together. I'm a childminder and found it such hard work having dd and my mindee (a year younger)
With a big(ish) age gap you get to enjoy them properly!