We used powder with Sam (except when out) and I loathed all the work in making up bottles.
Have only used ready feed so far with Oscar and love it, not just quick and convenient but none of that stress about not being sterile / debating about pre-making. Said I'd "treat" myself to it for the first 2 months but not sure I can bear to go back to powder!
Very expensive though - use Cow & Gate, he has nearly a full litre bottle a day at £2.69 so about £80 a month. Not sure how long I can justify that for!