This is my first answer on AskHistorians so I welcome corrections, criticism and expansion from the more experienced members of AskHistorians!

It's hard to answer this first part of your question, as a positive or negative effect on society is pretty subjective, but my amateur inquiry into this era leads me to believe I can answer regarding the economy side of the question, In the time period immediately leading up to and including the reign of King Alfred the Great, (10th c.)

The answer depends on what you were. For some the Viking raids were devastating economically. Monasteries were looted and stripped of their substantial wealth. Now, of course most of our sources on these raids come with a heavy bias-- a great deal of the chroniclers of that time period were Christians, and often clergy or monks. They tended to have a heavy doom and gloom mentality and a predilection for exaggerating the savagery, intensity, and destructive result of viking raids. There is no doubt however that there was significant financial loss to church institutions.

Additionally if you were a West Saxon king of say, Northumbria, Mercia or East Anglia, Viking arrival would prove devasting to your personal wealth and holdings. The kings of these three kingdoms tended to end up dead, exiled, replaced, or in subjugation to Viking sea warlords. In some cases the Vikings themselves supplanted the former Saxon rule and ruled as local kings themselves (Guthrum's rule over East Anglia after his surrender to King Alfred of Wessex at Chippenham), in other cases puppet kings were emplaced (Egbert was a Viking puppet in Northumbria).

However, subjugation or control by Vikings wasn't economically bad for everyone! By many accounts the City of York actually thrived under Viking control. York did very well trading with existing Viking trade networks, and had, while under Viking rule, access to silk from Byzantium, and wine from the European continent. York also developed some strong manufacturing, including metalwork, and successful mints. York and London both enjoyed profitable coin making, minting silver coins for both Viking rulers and Saxon rulers.

For some nobles, Viking rule may even have been perceived as preferable to loyalty to their Saxon king, which meant continued bloody warfare and expensive tribute levied from their coffers to bribe the Viking invaders. Alfred the Great seems to have been un-elected by his own witan (noble council) in a Viking backed coup just before his Athelney period (877).

Justin Pollard makes an excellent case for this in his book Alfred the Great: The Man Who Made England. If Viking rule was economically devastating for the local populace it seems unlikely that those of Alfred's nobles who were disloyal to him would have been willing to trade their own king for Guthrum. They must have perceived it as a trade up, economically and personally. Under Alfred's rule their levies were being called in to fight, and before Eddington generally Alfred's battles were not great victories, and Alfred was also reaching deep into his noblemen's (and clergy's) coffers to pay the punitively expensive tribute the Vikings were demanding.

Later in Alfred's campaign he was able to turn the tables, drive Guthrum out of Wessex, enforce a peace on Alfred's terms without tribute, baptise Guthrum and most of the candidates who might replace Guthrum into Catholicism, and even adopted Guthrum as his godson. Gutrhum withdrew to rule in East Anglia, seemed the have an easier time ruling Saxon people due to his new status, religion and ties to Alfred's ascendent Wessex. As far as the historical record uncovered so far shows-- did not trouble Alfred again. (Although after Guthrum's death Vikings from that area certainly did resume making trouble for Wessex.)

In summary, Viking rule would affect you economically in different ways depending on who you are and what your current stake in the status quo was. It was unquestionably harmful to many church institutions and the current ruling elite, but it could be very economically beneficial to submit to Viking rule, especially as was seen in York and to a lesser extent London.

My sources are written for laypeople, not academics but I believe they are well researched and considered accurate. I welcome correction or criticism on these sources from the real historians.

Sources:

Viking Age: Everyday life during the extraordinary era of the Norsemen - Kirsten Wolf

The Viking Wars of Alfred the Great - Paul Hill

Alfred the Great: The man who made England - Justin Pollard