I have very fair and thin eyebrows so I've spent my entire life pencilling and tinting my brows. (btw - a tip I learned for ladies who pencil is to always use a baby's toothbrush after pencilling to soften the line).
About 18 months ago I decided to take the plunge and have them tattooed, and I was overjoyed with the result. It was wonderful to get up in the morning and actually have eyebrows!!! If you go to someone with good qualifications and experience, they will make sure they discuss colour, shape etc before the procedure, and will draw the brows on first so you know exactly what they will look like. They will look a bit darker when they are first done, but they do lighten up over a month or so. The healing process is very minimal and provided they constantly use numbing cream during the procedure there is very little to no pain.
However, they definitely aren't permanent, which has its advantages and disadvantages. Depending on your skin type, cosmetic tattoos will only last from 1-5 years, because it's a different kind of tattooing to the regular types. For the conspiracy theorists (I'll put my hand up), maybe this is a rip-off designed for us vain women so they can constantly keep making money out us. Maybe there is no reason why they can't be made more permanent - I don't know.
However, the advantage of course is that you're not going to be stuck with it for the rest of your life, and the disadvantage is that you will need to keep getting it done.
My skin type is slightly oily on my forehead, and she told me mine would probably only last 12-18 months, and she was right. It's now 18 months since I had it done and all the tattooing is practically gone. I would be more than happy to get it done again, but it's very expensive, so I'm currently looking around and comparing prices.