Epson 3800 or online print service?
I have used MPIX and have some really nice prints, and some that are not as expected. To use a service, you either need to figure out how to match their profile, or allow them to color adjust. But if you let them adjust colors, it is subjective. Yes, I have a calibrated monitor.
Then I started printing art papers on my Epson R300 to see what I could get, I was amazed at the huge increase in punch. More saturation, more detail etc. I also have a chance to reprint of I screw up, or to print small proofs to get the color and sharpening right (Arghh, why do we have to sharpen an image, the camera guys need to fix that).
I will never have a large volume, and could never justify home printing based on cost. But the cost of a print on line is not as cheap as you think. To get a 16x24, you need to buy a 20x30 and have it trimmed because nobody makes 35mm format paper. Then you need to pay shipping, and you can’t mix sizes, so each different size gets a shipping charge.
The clincher, you can’t buy an image printed on Art paper. Photography is a hobby, I try to keeps the cost in reason, but adding the printing stage to the process is to add more to the hobby itself.