It comes down to time, confidence and how much support you have for me really. I had loans and shares on various part and grass livery arrangements, but then took on JR who was on DIY. I had support from a few friends on the yard, plus his owner.
I personally like DIY, although there are many times when I'd love someone to do the mucking out! Like Bexj said, it sometimes means you end up spending less time with your horse than you'd like - hours spent at yard dont always = hours spent with horse, unfortunately. Early last winter, I had 2 on straw and was spending so long mucking out and setting stables up, all the horses got was a quick once over and to bed - they were both out of work at the time, i don't know how i'd have managed if i'd had to ride them too!
Having said that, if you are committed enough I think can work really well - i like feeling like i'm the one caring for my horses every need, but a helpful YO or yard buddy who can turn out or fetch in occasionally is worth their weight in gold.