did they ever fail when they arrived?

"In the same year [878], the brother of Ivar and Halfdan sailed with twenty-three ships [approximately 1,200 men] from Dyfed, and came to Devon. There, acting on an erroneous assumption [that English defences would be unprepared], he met an unhappy death with 1,200 men at the hands of the King's thegns and in front of the stronghold at Cynuit."

This is one example from Asser's Vita Ælfredi, but one of a great number of examples both in Asser and in the Anglo-Saxon Chronicle of Viking raids that meet a sticky end in England. In fact, looking just between 882 and 885 alone (because I have that page open), Asser records a Viking fleet intercepted at sea and captured by the English, a Viking attack on Rochester fought off by the local garrison until Alfred's army arrives, and a failed Viking attack in Saxony driven off by the Frisians and the "Old Saxons."

By the late 9th Century, England had a sophisticated defensive network designed largely to prevent Viking raiding, and which the textual sources tell us worked very effectively. The fate of Viking raids cornered by vengeful English garrisons is illustrated by finds such as the Weymouth mass grave of what appears to be the execution and mass burial of an entire longship crew, apart from the heads of two men presumably taken as warning or as trophy.

After the more haphazard raiding of the early 9th Century, Viking raids are indeed part of a wider strategy, one based around rapid manoeuvre and destroying the enemy piecemeal before an organised response can be mustered. In the 871, for example, after the Battle of Ashdown, Asser complains that Wessex is being 'bled dry' by the massive manpower drain of having to have forces deployed to fight off 'countless' raids, and that as a result, Alfred and his brother are not able to muster anywhere near as many men as they would like for the main royal army. The aforementioned fleet which attempts to raid Devon in 878 is clearly aimed to coincide with the midwinter attack on Alfred at Chippenham, and the 'erroneous assumption' is that the English defences will be leaderless as a result. A similar strategy can be seen in the Viking raiding on Mercia in 910 which is defeated at the Battle of Tettenhall - the Vikings assume that Mercia will be an easy target as the West Saxon army is in East Anglia, and don't count on there being a Mercian resistance able to stop them raiding. Had such an attack succeeded, Edward the Elder would have been forced to pull his forces back from East Anglia to defend Wessex itself.

The Anglo-Saxon defensive strategy is based around the curtailment of the Viking strategy of movement and surprise which had clearly been so effective in the run-up to the Battle of Ashdown. The burh system establishes garrisons at fortified sites which control major river crossings, road junctions and the like, and are linked with an extensive network of local strongholds and signalling stations. This allows for an effective command and control network to prevent the Vikings making use of transport links, and instead use them to much more rapidly muster an organised military response to any threat. It is this rapid mustering and manouevring which allows Æthelred of Mercia to so effectively defeat the Vikings at Tettenhall, for example.

As a related side point, King Edgar (r.959-975) was known as 'The Peaceful' not because he didn't fight any wars, but because his maintenance of the English fleet and coastal defences was so successful that no attack on England survived to shore during his reign.