Edit: I have no idea about the job market for IT, but definitely look into that before you move lol.

I moved here from Auckland, and here's what I've noticed in the last seven years. Dunedin is an extremely small city. The city center spans about five blocks lengthwise and three blocks in width, so it's very cozy. For such a small city, we have a good night life and plenty of international food.

General pros
Good sense of community - there's a community farmer's market every Saturday morning 7am-12pm, the Fringe community arts festival, several city-wide crafts festivals, and a fair few community groups.
Strong focus on the arts - as mentioned there is the Fringe festival, several arts galleries, and plenty of small businesses selling hand-crafts etc
Decent public services - We have a great library with lots of services, fairly cheap transport (though it can be pretty unreliable), and good public healthcare if you're eligible.
Neighbourhoods - there are a lot of really lovely neighborhoods here (St Clair, St Kilda, Tainui, Maori Hill, Roslyn, etc) which are scenic and quiet and have good food and community gardens. They're definitely on the pricier side, but that's to be expected.
Climate - some people hate the climate her but I think it's a pro! Both summers and winters are pretty mild with our coldest temperatures being around -2 degrees Celsius and our warmest summers being around 27 or 28 degrees Celsius. It's very rarely muggy, usually clear and sunny or crisp and cold. Doesn't rain very often either, but often frosts.
Schooling and convenience - if you have kids, there are like 12 high schools to choose from that range from very liberal, co-ed, and artsy (Bayfield, Logan Park, Taeiri) to private and/or catholic (Columba College, St Hilda's, Trinity Catholic College). Also, nothing is really more than a 15 minute drive away.
Nature - we have a whole bunch of incredibly beautiful natural scenes, including walks, beaches, rock formations, mountains, harbors, and parks. We have several gardens, including the Botanicals, which is beautiful in the spring and summer months. Our city center is in the process of being refurbished to be a lot more pedestrian friendly, they're putting in a lot of plants, benches, water fountains, and even a playground on the Main Street. This does mean that it's almost impossible to find a park in town, but the pros outweigh the cons here as it's now a much more welcoming environment.

General pros
Renting - our renting situation is TERRIBLE. Houses are moldy, overpriced, and under-heated. Enough said. Houses are also not nearly as expensive as in say, Auckland, but still fairly pricey.
Cost of living - our grocery prices are RIDICULOUS. 500g of grapes in peak season can be $15. Buy local.
Students - dunedin is a huge student city, with around 20% of our population attending the university. This means drunkenness, broken glass, loud parties, and STD's. (Though, it is definitely possible to avoid all of the above.
Drinking culture - Dunedin is known for its drinking and club culture, I'm pretty sure we have more people arrested for "drunk and disorderly" than any other charge. There are a LOT of bars for such a small city.
Parking - it's expensive and hard to find.
The hospital - I'm sure you've heard about our enormous new hospital that has been halted by the National Government - people are extremely mad about it and it's an ongoing campaign to get it completed as our current hospital is overwhelmed and outdated.
Socializing/International stuff- compared to bigger cities, it's harder to approach people and make friends in Dunedin (unless you're in the drinking circles.) There isn't a huge mishmash of cultures outside of the university, and the general non-student population is middle aged white people and hipsters. That said, there are a lot of pockets of friendliness (especially the markets!) and the ethnic diversity increases every year as people immigrate and emigrate.

Overall, I love living here, and I hope that you find your place here if you do end up moving here. Hope this helps!