We have lived in Islington for nearly 2 years now. I wouldn't say don't live here but be careful which part. Also it depends what you are looking for. Looking for drunks at all hours of the day and night? Come to Islington! Looking for petty crime? Come to Islington! Looking for rip off parking fees? Come to Islington! Looking for teeenage tearaways? Come to Islington!
Sorry I am being a bit negative, Islington has many good qualities too, some nice green spaces, pretty architecture, decent neighbourhood pubs (stay away from Upper Street), tons of restaurants, a couple of decent clubs, lots of music venues, good transport links to other parts of the city. It is not as genteel as somewhere like Hampstead but nowhere near as rough'n'ready as nearby Hackney. We are just finding it suits our lifestyle less now that we have a baby and will probably move elsewhere soon.
Feel free to PM me if you have any specific questions about the area.
Liz