You are going to get mixed responses on this one. I'll break it down the way I figured it out.
First of all, a good kid replacer, top of the line, like Land-O-Lakes, has antibiotics and such. It's like feeding medicated feed to your chicks at first. Just gives them a little extra boost.
With cows milk, people have a lot of success with it, but you may have to supplement with some antibiotics. Think of it as getting a new puppy check ups. Or taking your kids to get booster shots.
I just weaned a baby goat and had to weigh out the cost as well as schedule for doing it both ways. The simplicity of the replacer won out for me.
Since you have raised others, I would stick with what you are comfortable with and what you know. Start giving regular goat feed and hay right away. It helps with weaning if they have already been introduced to it. Be careful of bloat. Goats have four stomachs and it will have to adjust to whatever you decide. Just be patient and walk it around, massage it's stomach to relieve it.
Good Luck with your decision.