I have the same experience as CC, I tried some of the local labs with some hit and miss results, more on the miss side. I tried Costco, they do okay for the price, but it always seems to have some sort of inconsistency about it, be it color or just looks flat. I can’t explain it but it just looks that way.
I don’t shop at Walmart, because I just feel like my IQ drops every time I enter the threshold of that store, not that my IQ is that high anyway, but I have to preserve what I have remaining.
Lately, I have been using Miller’s Lab with good results. I am not trying to make a commercial for them, because I am sure there are several other labs that do just as well, like Bay Photo, Century Color and National are some that pop into my head.
The paper I think makes a BIG difference. I have been using the Fuji Pearl Paper and it looks , IMO, just amazing. I try to convince my clients to select that paper when they order prints and I also keep several examples on hand to show the difference between that and the standard paper.
The way I look at it, I am a photographer, not a printer, I leave most of the printing work up to them. I don’t want to be burdened down with worrying about printer profiles or anything like that, so I let them worry about it. I try to make sure that they have a good clean image to use and plenty of room to crop as needed.
Sam thing with books and all the other products, just too much to worry about to do it myself.