I lived there for a year about six/seven years ago. I didn't find it any rougher than any other major provincial town in Ireland, to be honest. Sure, there are drugs in the town, but it doesn't have a massive drug problem or a big petty crime problem or anything like that. Don't listen to the rumours, it's not a bad town at all. It's what you would expect for a town of its size.
Of course, it all depends on where in the town you live. There are a few hairy estates up by the college on the Dublin Road. Stay out of Willow Park, for example, which is full of drunken students and boy racers. It's not a pretty estate, that's for sure.
My favourite part of the town was actually just over the bridge on the Roscommon side, in the 'Left bank' area of the town (as the locals like to aspirationally call it). This is the area around Sean's Bar and down by the riverside. There are some lovely little houses and cottages down there, and some nice cafes, restaurants etc.
Older areas of the town, like Coosan, can be hit and miss. The estates out there are older. It would be a bit like moving to parts of Crumlin/Kimmage in Dublin: settled, but not exactly white collar.
If you want the country feel, and don't mind a 15-minute drive, try a village just outside the town like Glasson - it is absolutely gorgeous.
There is loads of shopping in the town (Golden Island etc), with more slated (a brand new town centre development). There are plenty of pubs, although only a few nightclubs, and some decent restaurants.
I think it's a nice spot, only about 90 mins from Dublin, and it doesn't really deserve it's dodgy rep.