sRGB is the world's default colour space. Use it and your digital prints will look great. sRGB is the world standard for digital images, digital printing and the internet. Chances are your digital camera is preset to shoot sRGB .. unless you've played around with some of the default settings.
Adobe RGB squeezes colours into a smaller range which makes the colours look duller. Special software is needed to expand the colours back to where they should be when opening the file.
If you have the right software to re-expand the colours, theoretically you might have a slightly broader range of colours. However, if at any point in your workflow you don't have the right software and haven't attached the Adobe RGB profile, you will get duller colours as recorded.
Adobe RGB should never be used unless you really know what you're doing and do all of your printing yourself. You may find that Adobe RGB is used more often in the publishing industry using inkjet printers or laser printers.
Photo labs rarely have the right software to read Adobe RGB. This is why people who try to print real photos using Adobe RGB files are so often disappointed.
Paraphrased from an article written by Ken Rockwell