Before I answer this I should state that I am not impartial, and am a Labour Party supporter, but having said that I will try to keep my opinions neutral for this.
At the moment in terms of where it sits in the UK, it has no members of Parliament (MPs) so has no national influence. It does have the UK's largest number of European Parliament MPs, but as its aim is to leave the European Union it does not participate fully in that body. It has also aligned itself with a right wing grouping which does not have enough combined votes to have much influence.
In the UK the current third party in the Liberal Democrats, who went into coalition with the Conservatives following the general election in 2010, it would appear that UKIP wish to emulate this, having decided to target just 20 seats in 2015.
This seems to be a bid to gain influence, and in some parts UKIP is seen as a potential right wing adjunct to the conservatives.
UKIP has had some image troubles, with little control over selection of local candidates, including some elected members expressing racist and homophobic views - which is illegal in the UK.
I personally think that the views and policies of UKIP are unpleasant at best, and inflammatory at times, however their leader comes across in the media as a down to earth person who you would chat to in a bar.
Polling indicates that they have some support but not at the moment enough to generate a massive change in the makeup of the political landscape of the UK. And their support seems to be dropping following the EU elections.
You asked about support from business. From smaller businesses possibly yes, there has been some talk, but not any real UKIP announcement, on relaxing employment legislation, making it easier to fire people, but on the whole larger nationals / regionals/ multinationals are unlikely to be supportive, as if we were to leave the EU then businesses and imports would suffer.
Ukip have a strong anti migrant rhetoric, and organisations have been active in countering its views. Such As this Tuc booklet.
As to the final question about Scottish independence. I don't think they have that much influence with just one EU MP, and the Scottish wing of UKIP not functioning.