I lived in Harrisburg for 12 years. My family moved to Mechanicsburg a few miles away, however I lived in the city proper for 3 years before leaving. Harrisburg is an interesting place. An odd hybrid of Pittsburgh and Philadelphia. Lots of east coast attitude, but lots of rust belt earnestness as well.
First the positive: It's in the middle of EVERYTHING. NYC is 3 hours away, Baltimore/DC is 90 minutes, Philadelphia is 2.5 hours and Pittsburgh is 3 hours. Most beaches on the eastern shore are typically between 3-5 hours away depending on which one you're talking about. Pennsylvania is one of the oldest regions of the country and the historical significance of the area makes it an extremely attractive draw for US History buffs and casual tourists. The scenery in the entire central Pennsylvania area is green, lush and beautiful with thick forests, rolling hills, and winding back roads. The Susquehanna River which runs along the entire western border of the city is breathtaking on a sunny day. There are a pretty significant amount of things to do in Harrisburg, including restaurants, theater, music, concerts, and athletic events. Considering that the area isn't a large city, it's very surprising how much there is... it's not city-quality, but much of it is comes very close, minus all the big city hastles (crowding, traffic, high prices, etc.) Overall I would say the pluses outweigh the minuses in that respect.
The Negative: The worst thing about living in Harrisburg is the city itself. It's a dirty, dingy place with many destitute neighborhoods. The good part is that there isn't a whole lot of bleed-over from the bad areas to the good. They are very compartmentalized. Because of the massive amount of highways around the area, Harrisburg also has an extremely high pollution rate. Not a good place for allergy or asthma sufferers. Speaking of traffic, that's another huge problem. Harrisburg is the crossroads for about a dozen major state and interstate roads. In many areas containing the major traffic arteries there is no space to build on either side of the roads and therefore have too few lanes to accommodate the amount of traffic on them. Due to these factors the area highways are under constant strain and must be rebuilt constantly, causing lots of construction in the area, further exacerbating the traffic problems. Traffic often grinds to a halt with an incident on any of the major highways in the area. Another issue is he design of the highways. Many off ramps in and around the metro area are absurdly short or curved too far to allow any kind of acceleration until one is already off the exit ramp. Another minus is the provincial attitude of many of the residents. In many places you can expect to go out for drinks with your coworkers after hours, not here... everyone goes home to their families. This appeals to some, but not to others. While Pennsylvania is an extremely liberal place in the urban areas, it is just as conservative in the rural. Harrisburg is a blend of both, some extremely conservative, some extremely liberal. Overall I enjoyed living in Harrisburg very much. The people are friendly once you break through their tough exteriors, the weather is OK, it gets very rainy and gloomy in the autumn and there is often a large snow accumulation at least 3-5 times per winter. Summers are usually hot and humid.